"We found evidence that Neanderthal skin genes made Europeans and East Asians more evolutionarily fit," Benjamin Vernot says, "and that other Neanderthal genes were apparently incompatible with the rest of the modern human genome, and thus did not survive to present day human populations." (Credit: Beverly Goodwin/Flickr)

Neanderthal DNA lives on in our skin

A substantial fraction of the Neanderthal genome can still be found in the DNA of modern humans, new research suggests.

A new approach applied to analyzing whole-genome sequencing data from 665 people from Europe and East Asia shows that more than 20 percent of the Neanderthal genome survives in the DNA of this contemporary group, whose genetic information is part of the 1,000 Genomes Project.

Previous research proposes that someone of non-African descent may have inherited approximately 1 percent to 3 percent of his or her genome from Neanderthal ancestors. These archaic DNA sequences can vary from one person to another and were aggregated in the present study to determine the extent of the Neanderthal genome remaining in the study group as a whole.

The findings, published in the journal Science Express, are a start to identifying the location of specific pieces of Neanderthal DNA in modern humans and a beginning to creating a collection of Neanderthal lineages surviving in present-day human populations.

To check the accuracy of their approach, researchers ran their analysis before comparing the suspected Neanderthal sequences they found in modern humans to the recently mapped Neanderthal genome obtained from DNA recovered from bone. This genome came from the paleogenetics laboratory of Svante Paabo of the Max Planck Institute for Evolutionary Anthropology in Germany.

“We wanted to know how well our predictions matched the Neanderthal reference genome,” says Joshua M. Akey, associate professor of genome sciences at the University of Washington. “The analysis showed that, after more refinement of these methods, scientists might not need a reference genome from an archaic species to do this type of study.”

‘You need good data, too’

The results suggest that significant amounts of population-level DNA sequences might be obtained from extinct groups even in the absence of fossilized remains, because these ancient sequences might have been inherited by other individuals from whom scientists can gather genomic data, Akey says.

Therein lies the potential to discover and characterize previously unknown archaic humans that bred with early humans.

“In the future, I think scientists will be able to identify DNA from other extinct hominin, just by analyzing modern human genomes,” says graduate student Benjamin Vernot.

“From our end, this was an entirely computational project. I think it’s really interesting how careful application of the correct statistical and computational tools can uncover important aspects of health, biology and human history. Of course, you need good data, too.”

Neanderthals became extinct about 30,000 years ago. Their time on the earth, and some of their geographic range, overlapped with humans who anatomically resembled us.

The two closely related groups mated and produced some fertile offspring, such that portions of Neanderthal DNA were passed along to the next generations. In a proposed model, this mixing of DNA could have occurred both before and after the evolutionary divergence of non-African modern humans from a common ancestral population.

How many Neanderthal ancestors?

It didnt necessarily take a lot of individual hybrid offspring to introduce Neanderthal genes into early human populations. Still, Akey says that it isn’t known how many Neanderthal ancestors present-day humans have. But past interactions between the groups, is probably more complicated than previously thought.

“In addition, the analysis of surviving archaic lineages points to the possibility that there were fitness costs to the hybridization of Neanderthal and humans,” Akey says.

“I think what was most surprising to me,” Vernot says, “is that we found evidence of selection. Last year, I would have bet that a Neanderthal/human hybrid would have been as fit as a fully modern human. This was mostly because we haven’t been separated from them that long, on an evolutionary scale.”

More evolutionarily fit

Nevertheless, the Neanderthals were also a probable source for at least a few genetic variations that were adaptive for their human descendants. Neanderthal DNA sequences are found in regions of the genome that have been linked to the regulation of skin pigmentation. The acquisition of these variants by mating with the Neanderthals may have proven to be a rapid way for humans to adapt to local conditions.

“We found evidence that Neanderthal skin genes made Europeans and East Asians more evolutionarily fit,” Vernot says, “and that other Neanderthal genes were apparently incompatible with the rest of the modern human genome, and thus did not survive to present day human populations.”

The researchers observed that certain chromosomes arms in humans are tellingly devoid of Neanderthal DNA sequences, perhaps due to mismatches between the two species along certain portions of their genetic materials. For example, they noticed a strong depletion of Neanderthal DNA in a region of human genomes that contains a gene for a factor thought to play an important role in human speech and language.

According to the scientists, the “fossil free” method of sequencing archaic genomes not only holds promise in revealing aspects of the evolution of now-extinct archaic humans and their characteristic population genetics, it also might provide insights into how interbreeding influenced current patterns of human diversity.

Additionally, such studies might also help researchers hone in on genetic changes not found in any other species, and learn if these changes helped endow early people with uniquely human attributes.

 Source: University of Washington

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7 Comments

  1. Babu G. Ranganathan

    NEANDERTHALS WERE COMPLETELY HUMAN

    APES ARE QUITE COMFORTABLE IN HOW THEY WALK, just as humans are quite comfortable in how they walk. Even a slight change in the position of a tendon, muscle, bone, or cartilage for either, would be excruciatingly painful and would not be an advantage for survival. There’s no hard evidence that humans evolved from ape-like creatures anymore than there’s hard evidence that apes evolved from four-legged-pawed dog-like creatures. All the fossils that have been used to support human evolution have been found to be either hoaxes, non-human, or human, but not non-human and human (i.e. Neanderthal Man was discovered later to be fully human). Textbooks and museums still continue to display examples and illustrations supporting human evolution which most evolutionists have rejected and no longer support. Many diagrams of ape-man creatures over the years were reconstructed according to evolutionary interpretations from disputable bones that have now been discredited but still being taught in school textbooks.

    ACQUIRED CHARACTERISTICS CAN’T BE PASSED ON: Many people have wrong ideas of how evolution is supposed to work. Physical traits and characteristics are determined and passed on by genes – not by what happens to our body parts. For example, if a woman were to lose her finger this wouldn’t affect how many fingers her baby will have. Changing the color and texture of your hair will not affect the color and texture of your children’s hair. So, even if an ape’s muscles and bones changed so that it could walk upright it still would not be able to pass on this trait to its offspring. Only changes or mutations that occur in the genetic code of reproductive cells (i.e. sperm and egg) can be passed on to offspring.

    GENETIC AND BIOLOGICAL SIMILARITIES: Genetic information, like other forms of information, cannot happen by chance, so it is more logical to believe that genetic and biological similarities between all forms of life are due to a common Designer who designed similar functions for similar purposes. It doesn’t mean all forms of life are biologically related! Also, “Junk DNA” isn’t junk. These “non-coding” segments of DNA have recently been found to be vital in regulating gene expression (i.e. when, where, and how genes are expressed). Read my popular Internet article: HOW FORENSIC SCIENCE REFUTES ATHEISM

    HUMAN-CHIMP DNA MYTH: The actual similarity is between 70-87% not 99.8% as commonly believed. The original research stating 99.8% similarity was based on ignoring contradicting evidence. Read the article, “Evaluating the Human-Chimp DNA Myth–New Research Data” at the Institute for Creation Research Site. Whatever similarities exist are better explained due to a common Designer Who designed similar functions for similar purposes, rather than chance common ancestry. Read my Internet article: WAR AMONG EVOLUTIONISTS!

    NATURAL LIMITS TO EVOLUTION: Only evolution within “kinds” is genetically possible (i.e. varieties of dogs, cats, etc.), but not evolution across “kinds” (i.e. from sea sponge to human). How did species survive if their vital tissues, organs, reproductive systems were still evolving? Survival of the fittest would actually have prevented evolution across kinds! Read my Internet article: WAR AMONG EVOLUTIONISTS! (2nd Edition).

    Natural selection doesn’t produce biological traits or variations. It can only “select” from biological variations that are possible and which have survival value. The real issue is what biological variations are possible, not natural selection. Only limited evolution, variations of already existing genes and traits are possible. Nature is mindless and has no ability to design and program entirely new genes for entirely new traits.

    Modern evolutionists believe and hope that over, supposedly, millions of years random genetic mutations in the genes of reproductive cells caused by environmental radiation will generate entirely new genes. This is total blind and irrational faith on the part of evolutionists. It’s much like believing that randomly changing the sequence of letters in a romance novel, over millions of years, will turn it into a book on astronomy! That’s the kind of blind faith macro-evolutionists have.

    When evolutionary scientists teach that random genetic mutations in species over, supposedly, millions of years caused by random environmental agents such as radiation, produced entirely new genes (i.e. genetic code or genetic information) leading to entirely new forms of life, they are not teaching science but simply a faith, a belief!

    Also, so-called “Junk DNA” isn’t junk. Although these “non-coding” segments of DNA don’t code for proteins, they have recently been found to be vital in regulating gene expression (i.e. when, where, and how genes are expressed, so they’re not “junk”). Read my popular Internet article: HOW FORENSIC SCIENCE REFUTES ATHEISM

    Visit my newest Internet site: THE SCIENCE SUPPORTING CREATION

    I discuss: Punctuated Equilibria, “Junk DNA,” genetics, mutations,
    natural selection, fossils, genetic and biological similarities between species.

    Sincerely,
    Babu G. Ranganathan*
    (B.A. theology/biology)

    Author of popular Internet article, TRADITIONAL DOCTRINE OF HELL EVOLVED
    FROM GREEK ROOTS

    *I have had the privilege of being recognized in the 24th edition of Marquis “Who’s Who In The East” for my writings on religion and science. I have given successful lectures (with question and answer period afterward) before evolutionist science faculty and students at various colleges/universities.

  2. Mike

    Just who is this idiot what he has proposed to contradict mainstream science, where is the evidence or is it just faith ??? He lives in a cave in India

  3. Mike

    Well, Babu…that’s an interesting essay, but many of your contentions are simply factually incorrect, inaccurate repetitions of the same tired “debunking” of evolutionary theory that has been coming out of the Creationist/Intelligent Design camp for decades.

    Leaving that aside, however…since you appear to think that evolution is not valid, I’m surprised you did not use the considerable amount of space you took up here to present some repeatable, verifiable, peer-reviewed research that provides evidence for the validity of some other theory that you like better. I mean, the many opponents of evolution have had just as long to work on a better (and scientifically more valid) explanation than genetic modification through descent, haven’t they?

    What? There isn’t any such research or science? Well, there you go, then.

  4. TimeAndPlace

    There’s a time and a place for everything. These Kreationist Klowns keep popping up on scientific forums. Babu, what are the chances that we might be able to make a presentation in your church on Sunday, debunking your religion and replacing it with Darwin’s Theory of Evolution? Get back to me on that, will ya’? Until then, save your hubris for the choir. It’s nothing but annoying to the rest of us.

  5. The Second Mike

    FYI, visitors…the above comments, “Just who is this idiot…” and “Well, Babu” were written by two different Mikes. Second Mike has no idea whether Babu lives in a cave or not.

  6. Aaron

    LOL, some random guy with a Bachelor of Arts in Theology and Biology is attempting to lecture us on why years and years of carefully-compiled evidence for the claims made here are incorrect. All because he desperately wants his god to exist. Kinda sad.

  7. Erut

    Google Babu – he is apparently a fairly active creation “science” advocate. I’m surprised Hamm didn’t have him as a backup singer the other night

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