GENETICS: Unlocking Humanity's Past and Future

[Stormer0628]

GENETICS: WE ARE ALL AFRICANS
by George Busby |October 31, 2016

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Three new studies reveal the diversity of early human populations and help pin down when we left Africa.

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SUMMARY

• All humans across the globe right now—no exception—trace their roots to Africa.
  [*]Tracing the ancestor of all humans on Earth is a direct consequence of the Human Genome Project (HGP), the international scientific research project with the goal of determining the sequence of nucleotide base pairs which make up human DNA, and of identifying and mapping all of the genes of the human genome from both a physical and a functional standpoint.
  [*]Genetic and paleontological evidence show humans only started to leave Africa between 60,000 and 70,000 years ago.
  [*]What set this in motion is a major cataclysm, something to do with major climatic shifts that were happening around that time—a sudden cooling in the Earth’s climate driven by the onset of one of the worst parts of the last Ice Age.
• The last of our African ancestors who managed to survive and escape Africa were reduced to a population as low as 10,000—humanity was holding on by a thread at this time. It's the ultimate drama of human existence, one to stand for ages to come.
  [*]Genetics will revolutionize human societies in many ways not easy to imagine right now.

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Humans are a success story like no other. We are now living in the “Anthropocene” age, meaning much of what we see around us has been made or influenced by people. Amazingly, all humans alive today – from the inhabitants of Tierra del Fuego on the southern tip of the Americas to the Sherpa in the Himalayas and the mountain tribes of Papua New Guinea – came from one common ancestor.

We know that our lineage arose in Africa and quickly spread to the four corners of the globe. But the details are murky. Was there just one population of early humans in Africa at the time? When exactly did we first leave the continent and was there just one exodus? Some scientists believe that all non-Africans today can trace their ancestry back to a single migrant population, while others argue that there were several different waves of migration out of Africa.

Now, three new studies mapping the genetic profiles of more than 200 populations across the world, published in Nature, have started to answer some of these questions.

Aubrey Lynch, elder from the Wongatha Aboriginal language group, participated in one of the studies.
Image via Preben Hjort, Mayday Film.​

Out of Africa

Humans initially spread out of Africa through the Middle East, ranging further north into Europe, east across Asia and south to Australasia. Later, they eventually spread north-east over the top of Beringia into the Americas. We are now almost certain that on their way across the globe, our ancestors interbred with at least two archaic human species, the Neanderthals in Eurasia, and the Denisovans in Asia.

Genetics has been invaluable in understanding this past. While hominin fossils hinted that Africa was the birthplace of humanity, it was genetics that proved this to be so. Patterns of genetic variation – how similar or different people’s DNA sequences are – have not only shown that most of the diversity we see in humans today is present within Africa, but also that there are fewer differences within populations the further you get from Africa.

These observations support the “Out of Africa” model; the idea that a small number of Africans moved out of the continent – taking a much reduced gene-pool with them. This genetic bottleneck, and the subsequent growth of non-African populations, meant that there was less genetic diversity to go round, and so there are fewer differences, on average, between the genomes of non-Africans compared to Africans.

When we scan two genomes to identify where these differences, or mutations, lie, we can estimate how long in the past those genomes split from each other. If two genomes share long stretches with no differences, it’s likely that their common ancestor was in the more recent past than the ancestor of two genomes with shorter shared stretches. By interrogating the distribution of mutations between African and non-African genomes, two of the papers just about agree that the genetic bottleneck caused by the migration out of Africa occurred roughly 60,000 years ago. This is also broadly in line with dating from archaeological investigations.

Their research also manages to settle a long-running debate about the structure of African populations at the beginning of the migration. Was the small group of humans who left Africa representative of the whole continent at that time, or had they split off from more southerly populations earlier?

SGDP model of the relationships among diverse humans (select ancient samples are shown in red) that fits the data.
Image via Swapan Mallick, Mark Lipson and David Reich.​

The Simons Genome Diversity Project compared the genomes of 142 worldwide populations, including 20 from across Africa. They conclusively show that modern African hunter-gatherer populations split off from the group that became non-Africans around 130,000 years ago and from West Africans around 90,000 years ago. This indicates that there was substantial substructure of populations in Africa prior to the wave of migration. A second study, led by Danish geneticist Eske Willersev, with far fewer African samples, used similar methods to show that divergence within Africa also started before the migration, around 125,000 years ago.

More migrations?

Following the move out of the continent, the pioneers must then have journeyed incredibly quickly to Australia. The Danish study, the most comprehensive analysis of Aboriginal Australian and Papuan genomes to date, is the first to really examine the position of Australia at the end of the migration.

They found that the ancestors of populations from “Sahul” – Tasmania, Australia and New Guinea – split from the common ancestor of Europeans and Asians 51,000-72,000 years ago. This is prior to their split from each other around 29,000-55,000 years ago, and almost immediately after the move out of Africa. This implies that the group of people who ended up in the Sahul split away from others almost as soon as the initial group left Africa. Substantial mixing with Denisovans is only seen in Sahulians, which is consistent with this early split.

Crucially, because the ancestors of modern-day Europeans and Asians hadn’t split in two at this point, we think that they must have still been somewhere in western Eurasia at this point. This means that there must have been a second migration from west Eurasia into east Asia later on. The Simons Genome Diversity Project study, by contrast, albeit with a far smaller sample of Sahulian genomes, found no evidence for such an early Sahulian split. It instead shows that the ancestors of East Asians and Sahulians split from western Eurasians before they split from each other, and therefore that Denisovan admixture occurred after the former split from each other.

A graphic representation of the interaction between modern and archaic human lines, showing traces of an early out of Africa (xOoA) expansion within the genome of modern Sahul populations. Image via Dr. Mait Metspalu, Estonian Biocentre​

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Meanwhile, a third paper proposes an earlier, “extra” migration out of Africa, some 120,000 years ago. This migration is only visible in the genomes of a separate set of Sahulians sequenced as part of the Estonian Biocentre Human Genome Diversity Panel. Only around 2% per cent of these genomes can be traced to this earlier migration event, which implies that this wave can’t have many ancestors left in the present day. If true (the two other papers find little support for it), this suggests that there must have been a migration across Asia prior to the big one about 60,000 years ago, and that anatomically modern human populations left Africa earlier than many think.

Whatever the reality of the detail of the Out of Africa event, these studies provide some benchmarks for the timings of some of the key events. Importantly, they are also a huge resource of over 600 new and diverse human genomes that provide the genomics community with the opportunity for further understanding of the paths our ancestors took towards the Anthropocene.

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George Busby, Research Associate in Statistical Genomics, University of Oxford

This article was originally published on The Conversation. Read the original article.

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MIGRATION ROUTES

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When humans first ventured out of Africa some 60,000 years ago, they left genetic footprints still visible today. By mapping the appearance and frequency of genetic markers in modern peoples, we create a picture of when and where ancient humans moved around the world. These great migrations eventually led the descendants of a small group of Africans to occupy even the farthest reaches of the Earth.

Our species is an African one: Africa is where we first evolved, and where we have spent the majority of our time on Earth. The earliest fossils of recognizably modern Homo sapiens appear in the fossil record at Omo Kibish in Ethiopia, around 200,000 years ago. Although earlier fossils may be found over the coming years, this is our best understanding of when and approximately where we originated.

According to the genetic and paleontological record, we only started to leave Africa between 60,000 and 70,000 years ago. What set this in motion is a major cataclysm, something to do with major climatic shifts that were happening around that time—a sudden cooling in the Earth’s climate driven by the onset of one of the worst parts of the last Ice Age. This cold snap would have made life difficult for our African ancestors, and the genetic evidence points to a sharp reduction in population size around this time. In fact, the human population likely dropped to fewer than 10,000. We were holding on by a thread.

Once the climate started to improve, after 70,000 years ago, we came back from this near-extinction event. The population expanded, and some intrepid explorers ventured beyond Africa. The earliest people to colonize the Eurasian landmass likely did so across the Bab-al-Mandab Strait separating present-day Yemen from Djibouti. These early beachcombers expanded rapidly along the coast to India, and reached Southeast Asia and Australia by 50,000 years ago. The first great foray of our species beyond Africa had led us all the way across the globe.

Slightly later, a little after 50,000 years ago, a second group appears to have set out on an inland trek, leaving behind the certainties of life in the tropics to head out into the Middle East and southern Central Asia. From these base camps, they were poised to colonize the northern latitudes of Asia, Europe, and beyond.

Around 20,000 years ago a small group of these Asian hunters headed into the face of the storm, entering the East Asian Arctic during the Last Glacial Maximum. At this time the great ice sheets covering the far north had literally sucked up much of the Earth’s moisture in their vast expanses of white wasteland, dropping sea levels by more than 300 feet. This exposed a land bridge that connected the Old World to the New, joining Asia to the Americas. In crossing it, the hunters had made the final great leap of the human journey. By 15,000 years ago they had penetrated the land south of the ice, and within 1,000 years they had made it all the way to the tip of South America. Some may have even made the journey by sea.

The story doesn’t end there, of course. The rise of agriculture around 10,000 years ago—and the population explosion it created—has left a dramatic impact on the human gene pool. The rise of empires, the astounding oceangoing voyages of the Polynesians, even the extraordinary increase in global migration over the past 500 years could all leave traces in our DNA. There are many human journey questions waiting to be asked and answered.

What stories are waiting to be told in your own DNA?

 

[hardcorekid03]

Re: Genetics: All Humans Are Africans

 

[geozef]

Re: Genetics: All Humans Are Africans

Maitim narin kaya mga africans that time?

 

[Stormer0628]

Re: Genetics: All Humans Are Africans

Thanks.

Yung siggy mo ang ka-match ng thread na to.

- - - Updated - - -

Maitim narin kaya mga africans that time?

hehe.

Welcome!

 

[Stormer0628]

Re: Genetics: All Humans Are Africans

While representing the country in various international conventions and symposia, I sometimes find myself being drawn to counterparts from Vanuatu, Tonga, and Fiji. In one specific instance, I got especially close to this lumbering hulk of a man with such intimidating overgrown Afro haircut, massive physique, and ferocious stride that seemed to cause tremors in the immediate ground every time he took a step. Totally intimidated by the sheer aura of the man, I thought it wise to get out of his way whenever possible. I imagined I was big, but this one was just out of this world. It's like meeting Andre the Giant personally, but with the more primitive force of nature variety. But the man would sought me out, and draw me away to other reps from Fiji and Tonga. Turned out they loved the night life, and they knew the reputation of Filipinos in this regard. Of course I could not refuse, and soon learned the benefit of hanging out with those crowd: even the bar bouncers thought it wise not to provoke our group. Hah! Take that!

And then I remember how this man Asi Taulava happened. He entered the PBA draft, got into messy affairs with his ancestry, and almost totally missed the chance of playing here. The unfolding events brought back fresh memories of my friendly giants. What's up with these people anyway? Why are we suddenly finding ourselves getting close to them? Turned out the science of genetics has some answer today....

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The Curious Case of Asi Taulava:
Our Cousins from Tonga, Vanuatu, and Other Pacific Islands
Aftermath of the Out of Africa Project and the Largest Genomic Survey of Its Kind​

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Ancient DNA has revealed the first inhabitants of Vanuatu and Tonga came from Asia, especially the Philippines and Taiwan, not other Oceanic populations as has long been assumed, a study recently published found.

The study sheds light on the last great human migration into unpopulated lands, when a people called the Lapita fanned out into the South Pacific about 3,000 years ago.

Little is known of the mysterious culture beyond their distinctive dotted pottery and the human remains they left behind.

Scientists previously speculated that they were an offshoot of Australo-Papuan populations of Australia, New Guinea and the Solomon Islands, who arrived in the region 40,000-50,000 years ago.

But analysis of three skeletons from Vanuatu’s oldest cemetery found they came from Asia, with no trace of DNA from their Pacific neighbours.

View attachment 292468​

“Their original base population is Asian. They were straight out of Taiwan and ... the northern Philippines,” said Matthew Spriggs, a professor at the Australian National University and one of the researchers involved in the study.

“They travelled past places where people were already living, but when they got to Vanuatu there was nobody there. These are the first people.”

Spriggs said another DNA sample from a Lapita skeleton in Tonga returned similar results.

“We know this because testing conducted by two different laboratories in the United States and Germany confirm that the samples are of the same people,” he said.

He added that it now appeared the Asiatic Lapita first colonised the South Pacific, then intermingled with a second wave of Australo-Papuan settlers to create the region’s modern genetic mix.

Professor Ron Pinhasi from University College Dublin said the study, published in Nature, was made possible by improved methods of extracting material from skeletal remains.

“The unexpected results about Oceanian history highlight the power of ancient DNA to overthrow established models of the human past,” he said.
SOURCE

MORE

 

[Stormer0628]

Re: Genetics: All Humans Are Africans


I wanted to post the genetic tools used by the scientists to come up with the Out of Africa model, but found this related informative video while on it. So, before that next post, here's the video showing human population through time:

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About the video:
On Friday, the American Museum of Natural History released the above video, which maps the growth and migration of the human population from our origin as a species up to the present day.

Modern humans emerged around the horn of Africa around 200,000 years ago. The earliest example of Homo sapiens is Omo-1, a hunter whose 195,000 year old remains were found in Ethiopia’s Omo Valley in 1967. Modern humans began migrating out of Africa about 100,000 years ago, using land bridges to spread across the Middle East, Europe and Asia.

It took Homo sapiens sapiens 200,000 years to reach the first billion people, but for the majority of this time the human population was pretty small—likely less than one million people. There were a few near extinction events, such as the massive volcanic eruption in Sumatra about 70,000 years ago which may have left as few as 2000 humans alive.

With the advent of agriculture roughly 12,000 years ago, the human population began to balloon from an estimated five million in 8,000 BC to roughly 170 million people by AD 1. Over the next 2,000 years, things start to get pretty wild. The 1 billionth Homo sapiens sapiens was estimated to have been born around 1804 and person number 2,000,000,000 wouldn’t be born until 1927. That means within the last 90 years, we’ve managed to add an additional 5 billion people to the globe.

The 20th century human population boom is alarming and if current trends continue the global population will peak at approximately 11 billion people sometime around 2100. This means that population growth is actually slowing compared to what we’ve witnessed in the last 90 years, with fertility rates dropping in nearly every country.

The question posed by the American Museum of Natural History is how we are going to handle approaching spaceship Earth’s carrying capacity. The massive population boom over the last 200 or so years has put a strain on Earth’s resources already and another 4 billion people isn’t likely to help this scenario.

Instead, the Museum of Natural History advocates for family planning, reduced consumption, pollution controls, and habitat protection to mitigate the harms induced by projected human population growth. Because it may be relaxing to watch human population growth on a YouTube video set to ambient post-rock, but the reality on the ground will be fraught with violence linked to the increasing scarcity of resources.

 

[Stormer0628]

Re: Genetics: All Humans Are Africans

Here’s how genetics helped crack the history of human migration

View attachment 293062
A family migrating to western US in 1886. Marion Doss/Flickr, CC BY-SA​

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Over the past 25 years, scientists have supported the view that modern humans left Africa around 50,000 years ago, spreading to different parts of the world by replacing resident human species like the Neanderthals. However, rapid advances in genetic sequencing have opened up a whole new window into the past, suggesting that human history is much more complicated.

In fact, genetic studies in the last few years have revealed that since our African exodus, humans have moved and mixed a lot more than previously thought – particularly over the last 10,000 years.

The technology
Our ability to sequence DNA has increased dramatically since the human genome was first sequenced 15 years ago. In its most basic form, genetic analysis involves comparing DNA from different sets of people, whether between people with or without a particular type of cancer, or individuals from different regions of the world.

The human genome is 3 billion letters long, but as people differ at just one letter in every thousand, on average, we don’t have to look at them all. Instead, we can compare people where we know there are these differences, known as genetic markers. Millions of these markers have been discovered and, together with a genetic sequencing technology that allows us to cheaply look at these markers in lots of people, there has been an explosion in the data available to geneticists.

But while these analyses have shed light on different genetic associations, they have been unable to fully explain the genetic architecture of disease. It is becoming increasingly clear that rare genetic variants with small effects are likely to play a key role in genetic susceptibility to disease. And, because they are rare, finding these variants requires a whole-genome’s worth of sequence.

For that reason, the last ten years has also seen huge innovation in the technology available to read every letter of a genome. Today’s genome sequencing technologies typically work by breaking up DNA into billions of little pieces and then sequencing each of them separately but simultaneously in order to combine them into a full genome.

Out of Africa … and back
In addition to their use in medical genetics, these data are providing us with an increasingly sophisticated view of human history. When living things die, their DNA doesn’t disappear immediately; it slowly degrades over time. This means that the DNA of long dead people can still be found in fossils and skeletons, but it will be have been broken down into small pieces, perfect for modern sequencing technologies.

View attachment 293063
Map of early human migrations. Homo sapiens (red), Neanderthals (yellow-green), early hominids (yellow).​

Take the “out of Africa” theory as an example. Based on archaeology and limited genetics, the established view was that humans left Africa at some point within the last 100,000 years, spreading out to eventually inhabit the rest of the world, replacing older resident species of humans. While more advanced genetics has confirmed this to be roughly the case, it has also shown that it is not the full story.

Ancient DNA sequenced from fossils has taught us that, following the initial expansion out of Africa, the ancestors of non-Africans lived side-by-side and interbred with Neanderthals some 37,000 to 42,000 years ago, rather than just pushing them out. We also know that the ancestors of some Asian groups interbred with a different group of archaic human – known only from their DNA – called the Denisovans.

View attachment 293064
‘Why you don’t look so bad yourself.’ hairymuseummatt/wikimedia, CC BY-SA​

Ancient DNA also allows us to directly view the genomes of past populations. For example, we now know that in Europe, the farming revolution some 8,000 years ago was accompanied by the movement of people and was not just the spread of a clever idea. There was a subsequent mass migration of people into central Europe from the Russian Steppe which potentially brought Indo-European languages into the continent. A recent genetic study found that the ability of modern Europeans to digest the lactose in milk into adulthood may be traced to these migrants from Russia. It also traced blue eyes in modern Europeans back to European hunter gatherers of the Mesolithic period (10,000-5,000BC), while light skin may have come from migrants from the Middle East.

Further ancient population mixing happened in Africa when a significant movement of Eurasian people spread back into the continent within the last 3,000 years. In fact, one study estimated that between 4-7% of most African genomes may have come from this gene flow.

Analyses of modern-day human populations have shown that a lot of mixing has happened within the last 2,000 years, with populations moving both within and between continents. For example, during their expansions in the 13th century, the Mongols left a trail of DNA across Asia and into Eastern Europe, and towards the end of the first millennium AD, Arabs brought North and West African DNA into southern Europe. In effect, this means that populations did not extend to the far reaches of the world and remained in isolation. Once settled, these groups continued to share their DNA.

What this tells us is that our history is messy: we are all the product of a tangled bush of genetic relationships between different ancient and modern human groups. Our genes demonstrate that none of us can claim to have ancestry from just a single region or place, as people have been on the move throughout history. Food for thought indeed when migration is so high on the political agenda.
SOURCE

 

[Stormer0628]

Re: Genetics: All Humans Are Africans

Genetics

Designer Babies: How To Produce Super Geniuses

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For a long time, people have been looking for ways to produce a better generation. Many families want to have the next one be better in many ways. Usually, this is done by some having marriages arranged between families. Now in some ways, this can be produced through designer babies, and some families are looking for ways how to produce super geniuses.

There are people who would want their children to excel in education. There is much pride in parents who see their children do very well in school. Competition usually starts in schools as children try to vie for academic excellence. This has driven some people to find ways put the competition even higher, by trying to make super geniuses.

Having designer babies would be one way to do that. With genetic manipulation, slowly having the preferred offspring could be achieved. There is a question of ethics about this, though, and whether it would be good for society as a whole.

Michigan State University Professor Stephen Hsu said that within the next five to ten years, scientists would be able to do just that: map out and manipulate the 10,000 genes that make geniuses, as The Age reports. This can potentially have people choose what intelligence level their children will have.

Having designer babies might have some advantages, such as having children that can have a resistance or even immunity from certain diseases. This might be possible now with a tool called CRISPR/Cas9. This is used to move genes around, and it is very much real, according to SingularityHub.

CRISPR is being used to alter DNA by biologists. This is a powerful technology that could redefine how humans are made. Dr. Hsu that the future for designer babies is now much closer to reality than ever. Fears of ethics, as well as a society that might be ruled by the genetically endowed, come to mind with such things, but Dr. Hsu is confident about it.

He said that a world that has higher intelligence could have more people that can think more logically and rationally. A much orderly society could possibly be made. Designer babies would have more people that could possibly be much healthier, as such could be produced with fewer genetic defects.

The issue about ethics and having a stratified society would be there as discussions about designer babies go on. People will be there to know how to produce super geniuses and babies that have fewer diseases, all for a much better family. Such concerns are there, as in the case of the report that obesity is common among teens with autism.

 

[rapidox]

Re: Genetics: All Humans Are Africans

Meron episodes about genes/human genetics ng BBC horizon and PBS nova recently. In the near future daw pwede na ma edit yung genes at possible na magkakaron nang mga designer babies or maybe super human soldiers. lol

 

[Stormer0628]

Re: Genetics: All Humans Are Africans

Meron episodes about genes/human genetics ng BBC horizon and PBS nova recently. In the near future daw pwede na ma edit yung genes at possible na magkakaron nang mga designer babies or maybe super human soldiers. lol

Yan ang malaking issue sa CRISP-R tech na to. At di lang yan, almost every day may improvement sa technology. Pag ito ginamit sa kalokohan, may kalalagyan ang human race, tsk, tsk. Kawawa yung mga bansa na etsa pwera sa technology na to. Kaya kaliwa't kanan ang kaso ng mga inventors nito, alam nila paldo2 ang perang nakataya dito, virtual goldmine. Eh yung UK nung una mahigpit sa ganitong technology, ngayon fully allowed na nila. Natakot din maungusan.

Kawawa mga bansa talaga wala nito. Pano kung, let's say, malaking porsyento ng population ng advanced countries ipa-implement ito sa population nila. Paano na yung mga bata sa mahihirap na bansa, di lalong kulelat na sa competition. At least ang Singapore, South Korea, Taiwan, Japan, China very aware sa potential ng tech na to. Sa Pinas at ibang backward nations, langya hanggang ngayon nangangapa at tinatanong pa yung primitive questions kung totoo ba ang evolution. Ayan o, tao na ang pumapapel sa evolution and creation. I mean yung mga advanced nations lang pala.

 

[rapidox]

Re: Genetics: All Humans Are Africans

Wala tlga mananalo sa science vs religious ideology debate na yan, christian lunatic vs hard-line atheist.

 

[Stormer0628]

Re: Genetics: All Humans Are Africans

CRISPR gene-editing has been tested in a human for the first time
It could trigger a biomedical race between China and the US.
FIONA MACDONALD 15 NOV 2016

View attachment 293505​

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Chinese scientists have become the first in the world to inject an adult human with cells that have been genetically edited using the revolutionary CRISPR/Cas9 technique.

The CRISPR-edited cells were injected on October 28 by a team from the Sichuan University in Chengdu, as part of a clinical trial against aggressive lung cancer - and experts think it could trigger a biomedical race between the US and China.

If you haven't heard of CRISPR as yet, you soon will. The new gene-editing technique is poised to revolutionise the way we treat disease, by offering scientists a quick and easy way to cut and paste genes from our DNA.

CRISPR/Cas9 basically works like a pair of molecular scissors. Researchers just need to program it, and it can cut out certain genes - or add new ones - far more cheaply and quickly than any previous genetic tools.

Since the potential of the system was discovered back in 2012, it's already been tested widely in animals, and in January this year, it was used to successfully treat its first disease in mice, Duchenne muscular dystrophy.

There have also been CRISPR experiments done in non-viable human embryos, which were never brought to term.

But this is the first time that cells edited by CRISPR have ever been injected into an adult human.

The trial was carried out at the West China Hospital, and involved a patient with aggressive lung cancer. The researchers extracted the patient's immune cells from a blood sample and then used CRISPR editing to disable a gene in them.

The gene that was turned off codes for a protein called PD-1, which usually slows down a cell's immune response, allowing cancer to grow out of control.

These PD-1-free immune cells were then cultured in the lab and injected back into the patient. The aim is that they'll now proliferate in the patient's body and attack and destroy cancerous cells.

It's still early days, but lead researcher Lu You told David Cyranoski at Nature that the initial treatment went well, and the patient is now ready for a second injection.

Across the duration of the trial, which received ethics approval in July, the team aims to treat a total of 10 people, with between two and four injections of genetically edited immune cells each.

And they're not the only ones planning to use CRISPR on humans - the US has a similar trial against various cancers in the works, which is scheduled to start in early 2017, and has been funded by Napster billionaire Sean Parker.

And China has another three clinical trials planned for March 2017, which will investigate the use of CRISPR against bladder, prostate, and renal-cell cancers - although they're yet to receive funding and ethics approval for those.

All this activity leads experts to believe that we're in the midst of a new biomedical race between the US and China - like the space race, but this time the goal is efficient genetic editing.

"I think this is going to trigger 'Sputnik 2.0', a biomedical duel on progress between China and the United States," Carl June, an immunotherapist from the University of Pennsylvania and a scientific adviser on next year's US CRISPR trial, told Nature.

"[It's] important since competition usually improves the end product."

Other cancer researchers are excited about the progress, although it remains to be seen if the intensive process of individually removing, editing with CRISPR, and culturing patients' cells will be worth the end result.

This first Chinese trial will focus mainly on figuring out how safe the technique is, but hopefully in the coming months we'll also be able to get an idea of whether the technology works or not.

Either way, the fact that we're now able to edit people's genes so easily is a huge step forward for personalised medicine.

"The technology to be able to do this is incredible," Naiyer Rizvi from Columbia University Medical Centre, who wasn't involved in the study, told Nature.

The Chinese trial is still in the very early stages, and nothing has been published in a peer-reviewed journal as yet. But we'll be watching the results closely.
source

 

[MonkyDLuffy]

Re: Genetics: Defining Humanity's Past and Future

Hmmm....thankss

 

[Stormer0628]

Re: Genetics: Defining Humanity's Past and Future

Is Evolution Over? Synthetic Biology Anticipates Nature’s Next Steps
BY EDD GENTON SEP 09, 2016| BIOLOGY, FEATURED, GENETICS, SCIENCE 5,547 8
View attachment 293660
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Genetic engineering is introducing a gene from species A to species B. By allowing scientists to tinker with the genetic code at the heart of life, synthetic biology also may be accelerating our progress towards ... revolutionary adaptations​

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Some biological processes are so central to life as we know it that it’s tempting to assume all the key innovations in biochemistry have already happened.

Processes like photosynthesis and glycolysis have existed for millennia and are essential to the survival of countless species. But the Earth is only just over halfway through its habitable phase, with somewhere between 1.75 and 3.25 billion years of evolutionary time still stretched out ahead of us.

That means it’s highly likely revolutionary new processes at the heart of metabolic biochemistry will evolve before the Earth ceases to support life, according to a recent opinion piece in the journal Royal Society Biology Letters by Jodi Brewster, a post-doctoral fellow at the University of Otago in New Zealand, and her colleagues.

What those processes may look like is an open question, but Brewster says the nascent field of synthetic biology could offer glimpses of our evolutionary future. By allowing scientists to tinker with the genetic code at the heart of life, synthetic biology also may be accelerating our progress towards these revolutionary adaptations.

Synthetic biology is essentially an application of engineering principles to the fundamental molecular components of biology. Key to the process is the ability to design genetic circuits that reprogram organisms to do things like produce biofuels or excrete the precursors for pharmaceuticals, though whether this is commercially viable is another question.

MIT’s Jim Collins, one of the founders of synthetic biology, recently explained it to me as putting the engineering into genetic engineering.

“Genetic engineering is introducing a gene from species A to species B,” he said. “That’s the equivalent of replacing a red light bulb with a green light bulb. Synthetic biology is focused on designing the underlying circuitry expressing that red or green light bulb.”

As well as introducing entirely novel processes into cells, synthetic biologists have been working to refine those already there. Despite millions of years of evolution, some aspects of photosynthesis “remain woefully inefficient,” Brewster writes, and improved photosynthesis could have enormous impact on agricultural productivity.

Some researchers have attempted to transpose more efficient approaches to photosynthesis found in simpler organisms into crop plants.

Cyanobacteria achieve higher efficiency by concentrating CO2 in organelles called carboxysomes, which are filled with Rubisco, a key enzyme in the carbon fixation process. A group from Cornell engineered tobacco plants to express cyanobacterial Rubisco within carboxysome-like structures inside the plants’ chloroplasts, boosting their rate of carbon fixation. An Israeli team went further by combining existing metabolic building blocks from various organisms to design a host of synthetic carbon fixation pathways, some of which outperformed natural pathways.

Glycolysis — the metabolic pathway that releases energy from glucose — has comparable inefficiencies. Many pathways include a step where only four carbons from a six carbon sugar are put to good use, with the other two lost as CO2. This prompted a team from UCLA to design a synthetic pathway, dubbed non-oxidative glycolysis (NOG), that puts all six carbon atoms to good use.

Despite the huge amount of thought that has gone into these solutions to metabolic inefficiencies, according to Brewster and colleagues the amount of evolutionary time ahead of us means nature would be almost certain to stumble across them in the future anyway. The fact that horizontal gene transfer — where genetic material is transferred between species — is so common in bacteria makes this even more likely.

If these adaptations confer an evolutionary advantage, they are likely to proliferate through nature. Therefore, Brewster and colleagues say synthetic biology should be viewed as ‘biology not yet in the databases.’ The solutions synthetic biologists devise could have existed in the past, could simply be undiscovered, or could evolve in the future.

But by offering glimpses of future evolutionary events, synthetic biology may be accelerating that evolution.

Natural innovations in gene regulation have been central for major breakthroughs in the development of life, such as the emergence of multicellularity or complex developmental pathways. New innovations in gene regulation developed by synthetic biologists are likely to result in dramatic phenotypic changes in future organisms, say Brewster and colleagues.

The idea that nature would inevitably happen upon the innovations of synthetic biology may be overly simplistic. The researchers conclude “only time will tell whether there are viable evolutionary trajectories for realizing them in ways that increase organismal fitness,” but synthetic biology is not driven by survival of the fittest, it’s driven by the needs of humans.

Synthetic biology may result in biological systems that would never survive in nature. It’s hard to see how an adaptation to synthesize biofuel would offer an evolutionary advantage to bacteria in the wild. MIT’s Collins has already freed synthetic biology from the cell by freeze-drying synthetic gene circuits onto paper to act as biosensors. His MIT colleagues have even used synthetic biology to turn E. coli cells into living computers able to remember and respond to sequential input data.

While synthetic biology may be giving us new insights into where evolution could be leading us, it’s possible that evolution as we know it is over. Rather than nature being in the driver’s seat, we may be entering an age where humans are the guiding hand behind life’s bewildering complexity.
source

 

[Stormer0628]

Re: Genetics: Defining Humanity's Past and Future

We are all part virus — the role of human endogenous retroviruses
The Pharmaceutical Journal || by Kalliopi Dodou, Paul Whiteley

View attachment 294060

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Viruses lurk in our genome and science is only now starting to understand the important role that they might play in health and disease. ​

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The human genome — the collected blueprint of our heredity — is a remarkable piece of biological engineering. DNA represents the language of the information encoding the genome, which translates into genes, some of which subsequently code for specific proteins and shape important biochemical processes. The translation of DNA to protein expression is modified and controlled by countless biological actions often too varied and complex for us to comprehend.

The age of genomics — the study of the genome — continues at a pace with its focus on how various genetic mutations (eg, single nucleotide polymorphisms, copy number variants) shape our predisposition to numerous conditions impacting on our physical and psychological health.

The rise of epigenetics1 — the science of changes to gene function not explained by structural changes to the genome — further adds to the complexity and emphasizes how our genes are continually interacting with the environment around us. Far from being static entities, our genes are dynamic, variably switching on and off as a function of various different genetic, biochemical and environmental processes.

Although science is beginning to make in-roads into the complexity of how our genes shape our lives, curious things are also turning up in the genome. Regions of the genome, thought to contain only “junk DNA”, might not be so redundant as once thought. Even more surprisingly, our genomes might carry the battle scars of our evolutionary war with the forces of nature. In short, we are all hosts to viruses and hence, we are all part virus.

An absorbing process

Indeed, these additions to the genome are our spoils of conquest following generations of our ancestors at war with a multitude of microscopic viral invaders.

The constant bombardment of viral pathogens that the human race has fought off and developed immunity against down the ages has not been without consequences to our genome, as illustrated by the increasing interest in the role of endogenous retrovirus (ERVs) fragments and elements in health and disease.

Human endogenous retroviruses (HERVs) are the remnants of ancient retroviral infections, sometimes called fossil viruses, marked into our DNA via infection of germline cells (ie, the cells involved in reproduction).2 Passed down the generations, retroviral genes become part of the host genome and, gradually, generation after generation, pick up genetic mutations which eventually inactivate the virus, although still, in some cases, carrying the essential viral genes noted in exogenous retroviruses such as HIV. Around 4–8 per cent of the human genome is thought to comprise HERVs.3

Jumping genes

HERVs are part of the human mobile retrotransposon families or “jumping genes”. The idea that sequences of DNA might be mobile is perhaps one of the more surprising things about our genome. Indeed, this is all the more surprising when one discovers that such transposable elements may also be able to affect the function and expression of nearby genes depending on where they find themselves in the genome.4

Drawing on the increasing interest in the science of epigenomics, there is a growing acceptance that certain HERVs are, to some degree, kept in check by an epigenetic action. Depending on whether the long terminal repeats — the long, repeating sequences of DNA found at the ends of retrotransposons — are methylated or not, for example,5 seems to influence the subsequent effect on surrounding genes.

HERVs and health

It is still early days in terms of the research looking at how the expression of HERVs might influence health and well-being, although several themes have already emerged with regard to a possible action. Nelson and colleagues6 summarized some of the potentially important effects of HERVs listing them as potential modulators of gene or protein expression; potential superantigens, or potential agents of molecular mimicry, hence a candidate mechanism for the presentation of autoimmune conditions.

Looking specifically at the issues of molecular mimicry or HERVs as superantigens and onwards autoimmunity, Tugnet and colleagues7 provide an excellent overview looking specifically at the details of HERVs as possible triggers of autoimmune rheumatic disease. One particular theme is that of loss of tolerance — a key point in autoimmunity where the body fails to differentiate between self and foreign organisms. Although further investigation is indicated, one theory is that HERVs provide a continual source of antigen, fueling an immune response as a consequence of cross-reactivity with self-proteins.

As previously indicated, the role of an epigenetic influence on HERV expression may also play an important role in their link to autoimmune diseases. Nakkuntod and colleagues8 reported results based on the examination of methylation status of two HERVs — HERV-E and HERV-K — in lymphocytes from patients with systemic lupus erythematosus (SLE). They found that hypomethylation was a feature for SLE patients. The implication is that lower methylation levels will allow for expression of HERV genes, which may then have knock-on effects for processes such as molecular mimicry.

Various other conditions have also implicated HERVs as potential agents in their onset. Cancer research has, to some extent, taken on board the potential for HERVs to influence health.9 Reis and colleagues10 suggested that one particular class of HERV — a class II HERV-K element — related to betaretroviruses was frequently expressed in prostate cancer tissue specimens they analysed. They also noted that demethylation and androgen stimulation were regulators of gag-HERV-K protein expression and concluded that their findings were evidence of “one of the first bona fide retroviral cancer antigens in humans”. Similar results have been reported for other classes of HERVs, including in relation to gastrointestinal cancers11 and breast cancer.12

Some surprising HERV links

There is also a growing body of research literature suggestive of a link between HERVs and a variety of idiopathic conditions where genetics and biochemistry have not been fully elucidated. De Meirleir and colleagues13 reported preliminary results of immunoreactivity to HERV proteins in duodenal biopsies taken from patients diagnosed with myalgic encephalomyelitis (ME). They speculated that HERV expression may also have some connection to the expression of pro-inflammatory cytokines noted in cases of ME and some involvement with, or as a consequence of, the appearance of chronic inflammation.

HERVs have also been implicated in cases of schizophrenia and bipolar disorder. Perron and colleagues14 suggested that a specific HERV — HERV-W — may lie at an important intersection “between environmental, genetic and immunological factors” in relation to symptom onset. They suggested that activation of HERV-W by means of specific infections may have subsequent knock-on effects again with regard to inflammation and immune activation.

Other studies have also reported over-expression of other HERVs — HERV-H — in relation to conditions such as attention deficit-hyperactivity disorder15 and autism spectrum disorder.16 Although, again, there are still gaps in our knowledge of how HERVs may be related to these conditions and, indeed, any other comorbid conditions potentially present, it is interesting to note the results from Shuvarikov and colleagues17 pointing to a possible role for HERVs in mediating a genetic deletion which coincided with the appearance of autistic behaviours and other cognitive and development features.

Conclusions

There is a growing scientific interest in fossil viruses and how they may impact on health and well-being. Although a lot of focus has been directed to their relationship to the onset or progression of various diseases or conditions, it is likely that HERVs play a more multifactorial role purely as a consequence of their abundance in the genome and expression during important periods of development. Evidence for the mechanisms of how HERVs may link to specific conditions or states is accumulating based on central themes of their connection to immune function and perhaps more fundamental effects on the genome itself. More than that, however, HERVs provide us with an important link to our distant ancestors and illustrate how, from our basic understanding of our genome, our biological blueprint is turning out to be even more complicated than anyone could have ever imagined.

See also: Part human, part virus - what do we really know about DNA?

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References:

1 Dodou K. Whiteley P. DNA not necessarily your destiny? The growing role of epigenetics in pharmacy. The Pharmaceutical Journal 2013;290;23–4.

2 Griffiths DJ. Endogenous retroviruses in the human genome sequence. Genome Biology 2001:2:1017.

3 Lander ES, Linton LM, Birren B et al. Initial sequencing and analysis of the human genome. Nature 2001;409:860–921.

4 Slotkin RK, Martienssen R. Transposable elements and the epigenetic regulation of the genome. Nature Reviews Genetics 2007;8:272–85.

5 Lavie L, Kitova M, Maldener E et al. CpG methylation directly regulates transcriptional activity of the human endogenous retrovirus family HERV-K(HML-2). Journal of Virology 2005;79:876–83.

6 Nelson PN, Hooley P, Roden D et al. Human endogenous retroviruses: transposable elements with potential? Clinical and Experimental Immunology 2004;138:1–9.

7 Tugnet N. Rylance P, Roden D et al. Human endogenous retroviruses (HERVs) and autoimmune rheumatic disease: is there a link? The Open Rheumatology Journal 2013;7:13–21.

8 Nakkuntod J, Sukkapan P, Avihingsanon Y et al. DNA methylation of human endogenous retrovirus in systemic lupus erythematosus. Journal of Human Genetics 2013;58:241–9.

9 Yu HL, Zhao ZK, Zhu F. The role of human endogenous retroviral long terminal repeat sequences in human cancer (Review). International Journal of Molecular Medicine 2013;32:755–62.

10 Reis BS, Jungbluth AA, Frosina D et al. Prostate cancer progression correlates with increased humoral immune response to a human endogenous retrovirus GAG protein. Clinical Cancer Research 2013;19:6112–25.

11 Wentzensen N, Coy JF, Knaebel HP et al. Expression of an endogenous retroviral sequence from the HERV-H group in gastrointestinal cancers. International Journal of Cancer 2007;121:1417–23.

12 Wang-Johanning F, Li M, Esteva FJ et al. Human endogenous retrovirus type K antibodies and mRNA as serum biomarkers of early-stage breast cancer. International Journal of Cancer 2014;134:587–95.

13 De Meirleir KL, Khaiboullina SF, Frémont M et al. Plasmacytoid dendritic cells in the duodenum of individuals diagnosed with myalgic encephalomyelitis are uniquely immunoreactive to antibodies to human endogenous retroviral proteins. In Vivo 2013;27:177–87.

14 Perron H, Hamdani N, Faucard R et al. Molecular characteristics of human endogenous retrovirus type-W in schizophrenia and bipolar disorder. Translational Psychiatry 2012;2:e201.

15 Balestrieri E, Pitzianti M, Matteucci C et al. Human endogenous retroviruses and ADHD. The World Journal of Biological Psychiatry 2013 28 Nov 2013. [Epub ahead of print].

16 Balestrieri E, Arpino C, Matteucci C et al. HERVs expression in autism spectrum disorders. PLoS One 2012;7:e48831.

17 Shuvarikov A, Campbell IM, Dittwald P et al. Recurrent HERV-H-mediated 3q13.2-q13.31 deletions cause a syndrome of hypotonia and motor, language, and cognitive delays. Human Mutations 2013;34:1415–23.

Citation: The Pharmaceutical Journal, 1 March 2014, Vol 292, No 7799, p244 | DOI: 10.1211/PJ.2014.11135043

 

[Stormer0628]

Re: Genetics: Defining Humanity's Past and Future

How many genes to make a person?
by Sean Nee, Pennsylvania State University || EarthSky Voices in HUMAN WORLD
The answer—fewer than are in a banana—has implications for the study of human
health and raises questions about what generates complexity anyway.

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View attachment 294227
Do we contain the most elaborate set of instructions?​

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We humans like to think of ourselves as on the top of the heap compared to all the other living things on our planet. Life has evolved over three billion years from simple one-celled creatures through to multicellular plants and animals coming in all shapes and sizes and abilities. In addition to growing ecological complexity, over the history of life we’ve also seen the evolution of intelligence, complex societies and technological invention, until we arrive today at people flying around the world at 35,000 feet discussing the in-flight movie.

It’s natural to think of the history of life as progressing from the simple to the complex, and to expect this to be reflected in increasing gene numbers. We fancy ourselves leading the way with our superior intellect and global domination; the expectation was that since we’re the most complex creature, we’d have the most elaborate set of genes.

This presumption seems logical, but the more researchers figure out about various genomes, the more flawed it seems. About a half-century ago the estimated number of human genes was in the millions. Today we’re down to about 20,000. We now know, for example, that bananas, with their 30,000 genes, have 50 percent more genes than we do.

As researchers devise new ways to count not just the genes an organism has, but also the ones it has that are superfluous, there’s a clear convergence between the number of genes in what we’ve always thought of as the simplest lifeforms – viruses – and the most complex – us. It’s time to rethink the question of how the complexity of an organism is reflected in its genome.

View attachment 294229​

The converging estimated number of genes in a person versus a giant virus. Human line shows average estimate with dashed line representing estimated number of genes needed. Numbers shown for viruses are for MS2 (1976), HIV (1985), giant viruses from 2004 and average T4 number in the 1990s. Image via Sean Nee.​

Counting up the genes

We can think of all our genes together as the recipes in a cookbook for us. They’re written in the letters of the bases of DNA – abbreviated as ACGT. The genes provide instructions on how and when to assemble the proteins that you’re made of and that carry out all the functions of life within your body. A typical gene requires about 1000 letters. Together with the environment and experience, genes are responsible for what and who we are – so it’s interesting to know how many genes add up to a whole organism.

When we’re talking about numbers of genes, we can display the actual count for viruses, but only the estimates for human beings for an important reason. One challenge counting genes in eukaryotes – which include us, bananas and yeast like Candida – is that our genes are not lined up like ducks in a row.

Our genetic recipes are arranged as if the cookbook’s pages have all been ripped out and mixed up with three billion other letters, about 50 percent of which actually describe inactivated, dead viruses. So in eukaryotes it’s hard to count up the genes that have vital functions and separate them from what’s extraneous.

View attachment 294230
Megavirus has over a thousand genes, Pandoravirus has even more.​

In contrast, counting genes in viruses – and bacteria, which can have 10,000 genes – is relatively easy. This is because the raw material of genes – nucleic acids – is relatively expensive for tiny creatures, so there is strong selection to delete unnecessary sequences. In fact, the real challenge for viruses is discovering them in the first place. It is startling that all major virus discoveries, including HIV, have not been made by sequencing at all, but by old methods such as magnifying them visually and looking at their morphology. Continuing advances in molecular technology have taught us the remarkable diversity of the virosphere, but can only help us count the genes of something we already know exists.

Flourishing with even fewer

The number of genes we actually need for a healthy life is probably even lower than the current estimate of 20,000 in our entire genome. One author of a recent study has reasonably extrapolated that the count for essential genes for human beings may be much lower.

These researchers looked at thousands of healthy adults, looking for naturally occurring “knockouts,” in which the functions of particular genes are absent. All our genes come in two copies – one from each parent. Usually, one active copy can compensate if the other is inactive, and it is difficult to find people with both copies inactivated because inactivated genes are naturally rare.

Knockout genes are fairly easy to study with lab rats, using modern genetic engineering techniques to inactivate both copies of particular genes of our choice, or even remove them altogether, and see what happens. But human studies require populations of people living in communities with 21st century medical technologies and known pedigrees suited to the genetic and statistical analyses required. Icelanders are one useful population, and the British-Pakistani people of this study are another.

This research found over 700 genes which can be knocked out with no obvious health consequences. For instance, one surprising discovery was that the PRDM9 gene – which plays a crucial role in the fertility of mice – can also be knocked out in people with no ill effects.

Extrapolating the analysis beyond the human knockouts study leads to an estimate that only 3,000 human genes are actually needed to build a healthy human. This is in the same ballpark as the number of genes in “giant viruses.” Pandoravirus, recovered from 30,000-year-old Siberian ice in 2014, is the largest virus known to date and has 2,500 genes.

So what genes do we need? We don’t even know what a quarter of human genes actually do, and this is advanced compared to our knowledge of other species.

Complexity arises from the very simple

But whether the final number of human genes is 20,000 or 3,000 or something else, the point is that when it comes to understanding complexity, size really does not matter. We’ve known this for a long time in at least two contexts, and are just beginning to understand the third.

Alan Turing, the mathematician and WWII code breaker established the theory of multicellular development. He studied simple mathematical models, now called “reaction-diffusion” processes, in which a small number of chemicals – just two in Turing’s model – diffuse and react with each other. With simple rules governing their reactions, these models can reliably generate very complex, yet coherent structures that are easily seen. So the biological structures of plants and animals do not require complex programming.

View attachment 294231
The simple building blocks of neurons together generate immense complexity​

Similarly, it is obvious that the 100 trillion connections in the human brain, which are what really make us who we are, cannot possibly be genetically programmed individually. The recent breakthroughs in artificial intelligence are based on neural networks; these are computer models of the brain in which simple elements – corresponding to neurons – establish their own connections through interacting with the world. The results have been spectacular in applied areas such as handwriting recognition and medical diagnosis, and Google has invited the public to play games with and observe the dreams of its AIs.

Microbes go beyond basic

So it’s clear that a single cell does not need to be very complicated for large numbers of them to produce very complex outcomes. Hence, it shouldn’t come as a great surprise that human gene numbers may be of the same size as those of single-celled microbes like viruses and bacteria.

What is coming as a surprise is the converse – that tiny microbes can have rich, complex lives. There is a growing field of study – dubbed “sociomicrobiology” – that examines the extraordinarily complex social lives of microbes, which stand up in comparison with our own. My own contributions to these areas concern giving viruses their rightful place in this invisible soap opera.

We have become aware in the last decade that microbes spend over 90 percent of their lives as biofilms, which may best be thought of as biological tissue. Indeed, many biofilms have systems of electrical communication between cells, like brain tissue, making them a model for studying brain disorders such as migraine and epilepsy.

Biofilms can also be thought of as “cities of microbes,” and the integration of sociomicrobiology and medical research is making rapid progress in many areas, such as the treatment of cystic fibrosis. The social lives of microbes in these cities – complete with cooperation, conflict, truth, lies and even suicide – is fast becoming the major study area in evolutionary biology in the 21st century.

Just as the biology of humans becomes starkly less outstanding than we had thought, the world of microbes gets far more interesting. And the number of genes doesn’t seem to have anything to do with it.

Sean Nee, Research Professor of Ecosystem Science and Management, Pennsylvania State University
This article was originally published on The Conversation. Read the original article.

 

[giosangil]

Re: Genetics: Defining Humanity's Past and Future

wow! meron ba kaya traces of aliens?

 

[Stormer0628]

Re: Genetics: Defining Humanity's Past and Future

wow! meron ba kaya traces of aliens?

Flavor of the week (month?) ata tong aliens.

O ito, to spice up the topic even more:

View attachment 294461

Mystery alien genes: do we have an unknown ancestor?

by SHANNON VERHAGEN |JULY 29, 2016
Humans could potentially have another ancestor we didn’t know about

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View attachment 294462
Genome sequencing has revealed a mysterious new hominid ancestor.​

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NEW RESEARCH HAS discovered populations from South and Southeast Asia contain a small amount of ancestral DNA – not present in East Asians or Europeans – suggesting some modern humans have another, mystery ancestor.

The research – undertaken by Professor Jaume Bertranpetit from Pompeu Fabra University in Spain along with a team of researchers and published in Nature Genetics this week – involved whole-genome sequence analysis.

The genome sequences of 60 individuals of different ethnicities from India’s mainland were compared with those of 10 Andamanese individuals as well as publicly available data for other populations.

Unknown, extinct ancestor
The study found a small proportion of the genome sequence in populations from South and South East Asia contained DNA from an unknown, extinct, hominid ancestor.

Dr Alan Cooper, from the University of Adelaide and Australian Centre for Ancient DNA, said at least five ancestral hominids had been present in Southeast Asia – including Neanderthals, Denisovians, Homo floresiensis ('hobbits'), H. erectus and H. antecessor.

“We already knew there was another species or group of hominids in Southeast Asia who had contributed to the Denisovan genome,” commented Alan, who wasn't involved in this study.

“This paper further confirms that one other group, maybe the same one, has contributed to modern humans.”

This is not the first time ancestral DNA has been found in modern humans – when Homo sapiens (that's us) arrived in Southeast Asia about 60,000 years ago, they shared the space with the now extinct Denisovians – and today, Melanesians carry 4% of this ancestral DNA.

There is speculation over the mystery ancestor, with Alan suggesting Homo erectus (“upright man”) or an Asian Homo antecessor (“human pioneer”) as potential hominid groups of interest.

"A crowded stage"
However, without a well preserved specimen – the preservation process is hindered by Asia’s hot and humid climate – Alan said it will be difficult to determine the exact source of the genomic sequence.

“At the moment there’s not any good skeletal remains that are likely to provide DNA,” Alan said.

For now, the genetic information that is available can help scientists piece together what the ancestor potentially looked like.

“At the moment we are able to see the genetic shadow left behind in other genomes, but we’re not sure what fossils it is connected to," Alan said.

However, it could also be from a previously unidentified ancestral hominid. “I wouldn’t be surprised,” he added.

“What we can say safely is that Asia was a far more crowded stage.”

Read original article here

More: Mystery of our 145 'alien' genes: Scientists discover some DNA is NOT from our ancestors

 

[chikl3t]

Re: Genetics: Defining Humanity's Past and Future

mataas taas pa yung babasahin ko hahaha balikan ko nalang later

 

[Stormer0628]

Re: Genetics: Defining Humanity's Past and Future

mataas taas pa yung babasahin ko hahaha balikan ko nalang later

Hehe, oks lang manage your time. Di ko na nga rin naaasikaso yung ebook posts ko. Kung may specific title ka in mind let me know na lang bigyan kita kung meron ako.