Most people in the world share 2-4% of DNA with Neanderthals while a few inherited genes from Denisovans, a study confirms.
Denisovan
DNA lives on only in Pacific island dwellers, while Neanderthal genes
are more widespread, researchers report in the journal Science.
Meanwhile, some parts of our genetic code show little trace of our extinct cousins.
They include hundreds of genes involved in brain development and language.
"These
are big, truly interesting regions," said co-researcher Dr Joshua Akey,
an expert on human evolutionary genetics from the University of
Washington Medicine, US.
"It will be a long, hard slog to fully
understand the genetic differences between humans, Denisovans and
Neanderthals in these regions and the traits they influence."
Siberia cave
Studies
of nuclear DNA (the instructions to build a human) are particularly
useful in the case of Denisovans, which are largely missing from the
fossil record.
The prehistoric species was discovered less than a
decade ago through genetic analysis of a finger bone unearthed in a cave
in northern Siberia.
Image copyrightBENCE VIOLAImage caption
The Neanderthal remains were found in a cave in Siberia
Substantial
amounts of Denisovan DNA have been detected in the genomes of only a
handful of modern-day human populations so far. DNA of girl from Denisova cave gives up genetic secrets - BBC
"The
genes that we found of Denisovans are only in this one part of the
world [Oceania] that's very far away from that Siberian cave," Dr Akey
told BBC News.
Where the ancestors of modern humans might have had physical contact with Denisovans is a matter of debate, he added.
Denisovans
may have encountered early humans somewhere in South East Asia and,
eventually, some of their descendants arrived on the islands north of
Australia.
Meanwhile, humans repeatedly ran into Neanderthals as they spread across Eurasia.
"We
still carry a little bit of their DNA today," said Dr Akey. "Even
though these groups are extinct their DNA lives on in modern humans."
Genetic ancestry
The
research was carried out by several scientists, including Svante Paabo
of the Department of Evolutionary Genetics at the Max-Planck-Institute
for Evolutionary Anthropology.
They found that all non-African populations inherited about 1.5-4% of their genomes from Neanderthals.
However,
Melanesians were the only population that also had significant
Denisovan genetic ancestry, representing between 1.9% and 3.4% of their
genome.
"I think that people (and Neanderthals and Denisovans)
liked to wander," said Benjamin Vernot of the University of Washington,
who led the project.
"And yes, studies like this can help us track where they wandered."
The oldest ever human nuclear DNA to be reconstructed and sequenced
reveals Neanderthals in the making – and the need for a possible rewrite
of our own origins.
The 430,000-year-old DNA comes from mysterious early human fossils found in Spain’s Sima de los Huesos, or “pit of bones”.
The fossils look like they come from ancestors of the Neanderthals, which evolved some 100,000 years later. But a 2013 study found that their mitochondrial DNA is more similar to that of Denisovans (see video, below), who also lived later and thousands of kilometres away, in southern Siberia.
So who were the Sima people – and how are they related to us?
To find out, a team led by Matthias Meyer
at the Max Planck Institute for Evolutionary Anthropology in Leipzig,
Germany, pieced together parts of the hominin’s nuclear DNA from samples
taken from a tooth and a thigh bone.
One of the Sima de los Huesos skeletons
Javier Trueba, Madrid Scientific Films
The results suggest they are more closely related to ancestors of
Neanderthals than those of Denisovans – meaning the two groups must have
diverged by 430,000 years ago. This is much earlier than the
geneticists had expected.
It also alters our own timeline. We know that Denisovans and
Neanderthals shared a common ancestor that had split from our modern
human lineage. In light of the new nuclear DNA evidence, Meyer’s team
suggests this split might have happened as early as 765,000 years ago.
Previous DNA studies had dated this split to just 315,000 to 540,000 years ago, says Katerina Harvati-Papatheodorou at the University of Tubingen in Germany.
But a date of 765,000 years ago actually brings the DNA evidence more in line
with some recent fossil interpretations that also suggest an older
divergence between modern humans and the ancestor of the Neanderthals
and Denisovans.
“I am very happy to see that ideas about the divergence based on
ancient DNA and on anatomical studies of the fossil record seem to be
converging,” says Aida Gómez-Robles at George Washington University in Washington DC, who was involved in the fossil research.
Tree redrawn?
But if such an ancient split is correct, we might have to redraw parts of our evolutionary tree.
Conventional thinking is that modern humans, Neanderthals and Denisovans all evolved from an ancient hominin called Homoheidelbergensis.
However, H.heidelbergensis didn’t evolve until
700,000 years ago – potentially 65,000 years after the split between
modern humans and the Neanderthals and Denisovans.
Instead, another, obscure species called Homo antecessor might now be in the frame as our common ancestor.
This species first appeared more than a million years ago – and its face is very similar to that of modern humans, says Chris Stringer at the Natural History Museum in London.
Further puzzles
“Research must now refocus on fossils from 400,000 to 800,000 years
ago to determine which ones might actually lie on the respective
ancestral lineages of Neanderthals, Denisovans and modern humans,” he
says.
Another puzzle remains. The study confirmed a previous finding that
the mitochondrial DNA of the Sima hominin is more similar to Denisovans
than to Neanderthals – but no one knows why.
Perhaps there was another unidentified lineage of hominins in Eurasia
that interbred with the ancestors of both – but not with the particular
group of hominins that evolved into the Neanderthals.
Or, Meyer says, perhaps such mitochondrial DNA was typical of early
Neanderthals and Denisovans, and it was only later that Neanderthals
acquired different mitochondrial DNA from an African population of
“proto-Homosapiens“.
Journal reference: Nature, DOI: 10.1038/nature17405 Find out more about theoldest human genome dug up in Spain’s pit of bones:
Neanderthal diet: Only 20 percent vegetarian
Researchers have long debated the precise
diet of early humans, but the latest study is the first to nail down
precise percentages.
Fossil analysis suggests Neanderthals ate a diet of
80 percent meat. Photo by OrdinaryJoe/Shutterstock
TUBINGEN, Germany, March 14 (UPI) --
Neanderthals were apparently too busy hunting and scavenging to pay much
attention to Michael Pollan's dietary advice: eat mostly plants.
New isotopic analysis suggests prehistoric humans ate mostly meat. As detailed in a new study published in the journal Quaternary International, the Neanderthal diet consisted of 80 percent meat, 20 percent vegetables.
Researchers in Germany measured isotope concentrations of collagen in
Neanderthal fossils and compared them to the isotopic signatures of
animal bones found nearby. In doing so, scientists were able to compare
and contrast the diets of early humans and their mammalian neighbors,
including mammoths, horses, reindeer, bison, hyenas, bears, lions and others.
"Previously, it was assumed that the Neanderthals utilized the same
food sources as their animal neighbors," lead researcher Herve
Bocherens, a professor at the University of Tubingen's Senckenberg
Center for Human Evolution and Palaeoenvironment, said in a news release.
"However, our results show that all predators occupy a very specific
niche, preferring smaller prey as a rule, such as reindeer, wild horses
or steppe bison, while the Neanderthals primarily specialized on the
large plant-eaters such as mammoths and woolly rhinoceroses," Bocherens
explained.
All of the Neanderthal and animal bones, dated between 45,000 and
40,000 years old, were collected from two excavation sites in Belgium.
Researchers have long debated the precise diet of early humans, but
the latest study is the first to nail down precise percentages.
Bocherens and his colleagues are hopeful their research will shed light on the Neanderthals' extinction some 40,000 years ago.
"We are accumulating more and more evidence that diet was not a
decisive factor in why the Neanderthals had to make room for modern
humans," he said.
Humans Interbred With Hominins on Multiple Occasions, Study Finds
Photo
Skulls of the Neanderthal man.Credit
European Pressphoto Agency
The
ancestors of modern humans interbred with Neanderthals and another
extinct line of humans known as the Denisovans at least four times in
the course of prehistory, according to an analysis of global genomes
published on Thursday in the journal Science.
The interbreeding may have given modern humans genes that bolstered immunity to pathogens, the authors concluded.
“This
is yet another genetic nail in the coffin of our over-simplistic models
of human evolution,” said Carles Lalueza-Fox, a research scientist at
the Institute of Evolutionary Biology in Barcelona who was not involved
in the study.
The
new study expands on a series of findings in recent years showing that
the ancestors of modern humans once shared the planet with a surprising
number of near relatives — lineages like the Neanderthals and Denisovans
that became extinct tens of thousands of years ago.
Before
disappearing, however, they interbred with our forebears on at least
several occasions, and today we carry DNA from these encounters.
Later studies showed that the forebears of modern humans first encountered Neanderthals after expanding out of Africa more than 50,000 years ago.
But
the Neanderthals were not the only extinct humans that our own
ancestors found. A finger bone discovered in a Siberian cave, called
Denisova, yielded DNA from yet another group of humans.
Research
later indicated that all three groups — modern humans, Neanderthals and
Denisovans — shared a common ancestor who lived roughly 600,000 years
ago. And, perhaps no surprise, some ancestors of modern humans also
interbred with Denisovans.
Some
of their DNA has survived in people in Melanesia, a region of the
Pacific that includes New Guinea and the islands around it.
Those
initial discoveries left major questions unanswered, such as how often
our ancestors interbred with Neanderthals and Denisovans. Scientists
have developed new ways to study the DNA of living people to tackle
these mysteries.
Joshua
M. Akey, a geneticist at the University of Washington, and his
colleagues analyzed a database of 1,488 genomes from people around the
world. The scientists added 35 genomes from people in New Britain and
other Melanesian islands in an effort to learn more about Denisovans in
particular.
The
researchers found that all the non-Africans in their study had
Neanderthal DNA, while the Africans had very little or none. That
finding supported previous studies.
But
when Dr. Akey and his colleagues compared DNA from modern Europeans,
East Asians and Melanesians, they found that each population carried its
own distinctive mix of Neanderthal genes.
The first encounter happened when the common ancestor of all non-Africans interbred with Neanderthals.
The
second occurred among the ancestors of East Asians and Europeans, after
the ancestors of Melanesians split off. Later, the ancestors of East
Asians — but not Europeans — interbred a third time with Neanderthals.
Earlier
studies had hinted at the possibility that the forebears of modern
humans had multiple encounters with Neanderthals, but until now hard
data was lacking.
“A
lot of people have been arguing for that, but now they’re really
providing the evidence for it,” said Rasmus Nielsen, a geneticist at the
University of California, Berkeley, who was not involved in the new
study.
An analysis of the genome of a Siberian Neanderthal, published today in Nature,
reveals for the first time that humans contributed DNA to the
Neanderthal genome about 100,000 years ago; that's 50,000 years earlierthan the previous estimate. The finding points to an earlier departure from Africa for our human ancestors.
Between 1 and 7 percent of the Siberian Neanderthal’s genome was human—
inherited from people who migrated out of Africa. That suggests humans
and Neanderthals interbred several times. But it also alters our
understanding of human history. Since Neanderthals didn’t make it to
Africa, humans must have left about 50,000 years earlier than
evolutionary biologists had previously estimated. And that's big news,
says Sergi Castellano,an evolutionary biologist at the Max
Planck Institute for Evolutionary Anthropology in Germany and a
co-author of the study. This is "thefirst piece of genetic evidence" that some modern humans "were already out of Africa" 100,000 years ago, he says.
Humans left their mark on Neanderthals, too
Previous genetic analyses have revealed that humans interbred with Neanderthals less than 65,000 years ago, outside of Africa. As a result, Europeans and Asians inherited between 1 and 4 percent of
their DNA from Neanderthals. And that DNA still has an effect on humans
today; just last week scientists linked Neanderthal DNA to a wide range of human health conditions, including depression and nicotine addiction.
But until now, what researchers knew about Neanderthal-human
interactions came from studying the flow of genes from Neanderthals to
humans — and not the other way around. That's mostly because researchers
didn't have the kinds of technologies or the appropriate Neanderthal
DNA samples that would allow them to search in the opposite direction.
This is the first time that scientists have been able to find evidence
that humans left their genetic mark on Neanderthals as well, says
Laurent Frantz, an evolutionary biologist at the University of Oxford
who didn't work on the study. A Siberian Neanderthal with human DNA
To arrive at these conclusions, Castellano and his team searched the
complete genome of a Neanderthal discovered in a Siberian Cave in 2010.
They found that certain regions of the Neanderthal's genome was closely
related to those found in African human populations today. To estimate
the timing of the interbreeding event, the researchers performed a
statistical analyses based on the size and the clustering of the DNA
fragments. This technique works because researchers know that when
animals reproduce, their genetic material mixes with that of other
animals; this causes individual DNA fragments belonging to one
individual to break into smaller pieces as they're passed down through
generations. In this particular case, the technique revealed that the
Siberian Neanderthal's ancestors interbred with humans some 100,000
years ago. Neanderthal toe bone (Bence Viola)
The researchers verified their findings by looking at the genome of a
Denisovan — a member of an extinct human species that split off from
Neanderthals some 380,000 years ago, after Neanderthals became a
subspecies distinct from modern humans. Because Denisovans are more
closely related to Neanderthals than they are to humans, their genomes
can help scientists figure out the kinds of genetic mutations that are
typical of these human subspecies. The analysis showed no evidence of
the human DNA fragments in the Denisovan's genome, which suggests that
these genetic elements were introduced in the Siberian Neanderthal's
genome after Denisovans and Neanderthals evolved away from each other.
Castellano and his team also compared genetic material on chromosome
21 for the Siberia Neanderthal and two different populations of European
Neanderthals. The scientists found no evidence of human integration in
the European samples, which means that ancestors of the introduction of
human DNA into the Siberia Neanderthal probably happened after the
Siberian population branched off from the European Neanderthals, around
110,00 years ago. "This is a big milestone."
The study "doesn't change what we knew before; it's building on it,"
Frantz says. Instead, it gives scientists a better understanding of how
many times human and Neanderthals met. "This is a big milestone," he
says.
Sarah Tishkoff, an evolutionary biologist at University of
Pennsylvania who didn't work on this study, agrees. "This is really
exciting work because it changes what we thought about human
evolutionary history."Butshe also says that the the
comparison of chromosome 21 means that researchers could be missing
signs of human DNA integration in the rest of the European genomes. In
addition, the study doesn't actually reveal much about the interbreeding
event itself. Even though the Neanderthal in the study was found in
Siberia, the human-neanderthal interactions probably occurred further
south, Tishkoff says. But where exactly those interactions happened is a
mystery. The fate of these adventurous humans is also unclear, Frantz
says. "The population is probably partly extinct, and partly integrated
in many different populations across the world."
The study raises a ton of questions, but for now the findings suggest
that what we thought we knew about humans and Neanderthals is just one
tiny piece of the puzzle. "There could have been multiple [human]
migrations coming out of Africa, and some groups just didn't make it,"
Tishkoff says. Research like this helps "paint a picture of what the
ancestry was, not just of modern humans, but of Neanderthals; and that
picture was more complex than we thought."
DNA was taken from ancient human bones, like this skull, from the Dolnte Vestonice burial site in the Czech Republic
L. Lang
Europe went through a major population upheaval about 14,500 years
ago, at the end of the last ice age, according to DNA from the bones of
hunter-gatherers. Ancient DNA studiespublished
in the last five years have transformed what we know about the early
peopling of Europe. The picture they paint is one in which successive
waves of immigration wash over the continent, bringing in new people,
new genes and new technologies.
These studies helped confirm that Europe’s early hunter-gatherers –
who arrived about 40,000 years ago – were largely replaced by farmers
arriving from the Middle East about 8000 years ago. These farmers then
saw an influx of pastoralists from the Eurasian steppe about 4500 years
ago, meaning modern Europe was shaped by three major population turnover events.
Waves of immigration
The latest study suggests things were even more complicated. About 14,500 years ago, when Europe was emerging from the last ice age,
the hunter-gatherers who had endured the chilly conditions were largely
replaced by a different population of hunter-gatherers.
Exactly where this new population came from is still unclear, but it
seems likely that they came from warmer areas further south. “The main
hypothesis would be glacial refugia in south-eastern Europe,” says Johannes Krauseat the Max Planck Institute for the Science of Human History in Jena, Germany, who led the analysis.
As conditions improved, it was these southern hunter-gatherers who
took advantage and migrated into central and northern Europe, he says –
meaning there was a genetic discontinuity with the hunter-gatherer
populations that had lived there earlier.
Martin Frouz
His team analysed mitochondrial DNA extracted from 55 ancient
Europeans, the oldest of whom lived 35,000 years ago – during the
Pleistocene – and the youngest just 7000 years ago, during the Holocene.
Previous studies focused largely on the Holocene, looking at human
remains from the last 10,000 years.
“This is the first glimpse at Pleistocene population dynamics in
Europe,” says Krause. “Little has been done on this older material,
mostly due to lower abundance of material and lesser preservation due to
age.”
“The population turnover after 14,500 years ago was completely unexpected,” says Iosif Lazaridisat
the Harvard Medical School in Boston. “It seems that the
hunter-gatherers of Europe braved the worst of the ice age during the
last glacial maximum but were then replaced when the ice age had begun
to subside.”
Europe’s unusual history
The picture is not yet clear, however, as the study only looked at
mitochondrial DNA sequences, rather than the longer nuclear DNA of other
studies. “Mitochondrial DNA tells only part of the story of a
population,” says Lazaridis. It is important to try to extract nuclear
sequences from the Pleistocene-aged skeletons to find out more about
this earlier population turnover, he says.
The work also may solve a long-standing mystery of why a certain
genetic signature is missing in people of European ancestry. All people
today are members of one of a relatively small number of distinct groups
based on their mitochondrial DNA, which is passed down the maternal
line. The distribution of people in each group gives us a sense of how humans spread across the world in prehistory.
It always seemed that Europe had a very unusual history of
colonisation because one major haplogroup – the M clade – is almost
entirely missing, despite being very common across Asia and even found in Native Americans. Instead, another major haplogroup – the N clade – is most common.
“Some authors had argued that the M and N haplogroups represented two different dispersal events from Africa,” says Toomas Kivisild at the University of Cambridge.
But Krause and his colleagues found that the M clade might actually
have been common in Europe before the population turnover 14,500 years
ago: three of the 18 most ancient humans they studied belonged to the M
clade.
This suggests that the initial colonisation of Europe and Asia may
have involved the same ancient population – and that the M group was
actually lost in Europe much later, perhaps connected in some way to the
mystery upheavals 14,500 years ago.
Journal reference: Current Biology, DOI: 10.1016/j.cub.2016.01.037 Read more:The three ancestral tribes that founded Western civilisation
Europe wasn't a very hospitable place fifteen millennia ago. The
westernmost landmass of the Eurasian continent had endured a long ice
age, with glaciers stretching across northern Europe and into the region
we now call Germany. But suddenly, about 14,500 years ago, things
started to warm up quickly. The glaciers melted so fast around the globe
that they caused sea levels to rise 52 feet in just 500 years.
Meanwhile, the environment was in chaos, with wildlife trying vainly to
adjust to the rapid fluctuations in temperature. Humans weren't immune
to the changes, either.
A new, comprehensive analysis of ancient European DNA published today in Current Biology magazine
by an international group of researchers reveals that this period also
witnessed a dramatic shift in the human populations of Europe.
Bloodlines of hunter-gatherers that had flourished for thousands of
years disappeared, replaced with a new group of hunter-gatherers of
unknown origin.
Researchers discovered this catastrophic population meltdown by
sequencing the mitochondrial DNA of 35 people who lived throughout
Europe between 35 and 7 thousand years ago. Mitochondrial DNA is a tiny
amount of genetic material that's inherited virtually unchanged via the
maternal line, and thus it serves as a good proxy for relatedness over
time. Two people from the same maternal stock share almost the same
mitochondrial DNA, even if separated by thousands of years, because this
kind of DNA evolves very slowly.
It's long been known that two such related groups, called M clade and
N clade, poured out of Africa and across the Eurasian continent about
55 thousand years ago. Some of these people wandered so far that they
even made it to Australia, eventually. And yet something rather odd
happened to the people of Europe. Only members of the N clade survived
into the present day, while Asia, Australia, and the Americas are full
of the offspring of both N and M. Until the new study in Current Biology,
scientists believed that the most likely explanation was that roughly
45 thousand years ago, Europe was colonized solely by the N clade, while
both clades settled elsewhere around the world.
But thanks to sequencing the mitochondrial DNA in those 35 ancient
people, the researchers uncovered something previously unknown. There
were, in fact, people from the M clade alive in Europe as recently as 25
thousand years ago. But something happened to wipe them out during the
cold, dry glacial maximum that gripped the world between 25 and 14.5
thousand years ago.
Enlarge/
In this image, you can see the clades of the people
who the team
sequenced, and how they fared over time. The
R and U clades are all
descended from the N clade. Note that
M is present until 25 thousand
years ago, when the ice age begins.
Current Biology
There are obvious reasons why Europeans might have suffered a
population bottleneck during the ice age, or the Last Glacial Maximum.
Food was scarce, and once-fecund habitats became unlivable. Groups that
once roamed the wide-open fields of Europe retreated into small refuges,
separated by walls of ice or frozen drought wastelends created when
glaciation locks up atmospheric water. The researchers believe that the M
clade, whose members were found far to the north, may have slowly died
out during that period. After the glaciers retreated, the survivors
were replaced by a new N-related population from elsewhere on the
continent.
Write the researchers:
The potential impact of climatic events on the
demography, and thus the genetic diversity of early Europeans, has
previously been difficult to quantify, but it likely had consequences
for the relative components of ancient ancestry in modern-day
populations. Our demographic modeling reveals a dynamic history of
hunter-gatherers, including a previously unknown major population shift
during the Late Glacial interstadial (the BøllingAllerød, 14.5 ka).
Under our best-fitting model, the small initial founder population of
Europe slowly grows up until 25 ka and survives with smaller size in LGM
[Last Glacial Maximum] climatic refugia (25–19.5 ka) before
re-expanding as the ice sheets retract. Although this model supports
population continuity from pre- to post-LGM, the genetic bottleneck is
consistent with the apparent loss of hg M in the post-LGM. Globally, the
early warming phases of the Late Glacial are strongly associated with
substantial demographic changes, including extinctions of several
megafaunal species and the first expansion of modern humans into the
Americas. In European hunter-gatherers, our model best explains this
period of upheaval as a replacement of the post-LGM maternal population
by one from another source.
Essentially, an entire genetic line in Europe was wiped out by
climate change. You might say that today's European population still
bears the scars of an ancient ice age in its mitochondrial DNA. Current Biology, 2016. DOI: 10.1016/j.cub.2016.01.037.
Why Did Ancient Europeans Just Disappear 14,500 Years Ago?
By Tia Ghose
March 2, 2016 11:22 AM
The skull of a man who lived between 36,200
and 38,700 years ago in Kostenki in western Russia.
Some of Europe's earliest inhabitants mysteriously vanished
toward the end of the last ice age and were largely replaced by others, a
new genetic analysis finds.
The finds come from an analysis of dozens of ancient fossil remains collected across Europe.
The genetic turnover was likely the result of a rapidly changing
climate, which the earlier inhabitants of Europe couldn't adapt to
quickly enough, said the study's co-author, Cosimo Posth, an
archaeogenetics doctoral candidate at the University of Tübingen in
Germany.
[Top 10 Mysteries of the First Humans]
The temperature change around that time was "enormous compared to the
climactic changes that are happening in our century," Posth told Live
Science. "You have to imagine that also the environment changed pretty
drastically." A twisted family tree
Europe has a long and tangled genetic legacy. Genetic studies have revealed that the first modern humans who poured out of Africa, somewhere between 40,000 and 70,000 years ago, soon got busy mating with local Neanderthals. At the beginning of the agricultural revolution, between 10,000 and 12,000 years ago, farmers from the Middle East
swept across Europe, gradually replacing the native hunter-gatherers.
Around 5,000 years ago, nomadic horsemen called the Yamnaya emerged from
the steppes of Ukraine and intermingled with the native population. In
addition, another lost group of ancient Europeans mysteriously vanished about 4,500 years ago, a 2013 study in the journal Nature Communications found.
But relatively little was known about human occupation of Europe between the first out-of-Africa event and the end of the last ice age,
around 11,000 years ago. During some of that time, the vast Weichselian
Ice Sheet covered much of northern Europe, while glaciers in the
Pyrenees and the Alps blocked east-west passage across the continent. Lost lineages
To get a better picture of Europe's genetic legacy during this cold
snap, Posth and his colleagues analyzed mitochondrial DNA — genetic
material passed on from mother to daughter — from the remains of 55
different human fossils between 35,000 and 7,000 years old, coming from
across the continent, from Spain to Russia. Based on mutations, or
changes in this mitochondrial DNA, geneticists have identified large
genetic populations, or super-haplogroups, that share distant common
ancestors.
"Basically all modern humans outside of Africa, from
Europe to the tip of South America, they belong to these two
super-haplogroups that are M or N," Posth said. Nowadays, everyone of
European descent has the N mitochondrial haplotype, while the M subtype
is common throughout Asia and Australasia.
The team found that in
ancient people, the M haplogroup predominated until about 14,500 years
ago, when it mysteriously and suddenly vanished. The M haplotype carried
by the ancient Europeans, which no longer exists in Europe today,
shared a common ancestor with modern-day M-haplotype carriers around
50,000 years ago.
The genetic analysis also revealed that
Europeans, Asians and Australasians may descend from a group of humans
who emerged from Africa and rapidly dispersed throughout the continent
no earlier than 55,000 years ago, the researchers reported Feb. 4 in the
journal Current Biology. Time of upheaval
The team suspects this upheaval may have been caused by wild climate swings.
At the peak of the ice age, around 19,000 to 22,000 years ago, people
hunkered down in climactic "refugia," or ice-free regions of Europe,
such as modern-day Spain, the Balkans and southern Italy, Posth said.
While holdouts survived in a few places farther north, their populations
shrank dramatically.
Then around 14,500 years ago, the
temperature spiked significantly, the tundra gave way to forest and many
iconic beasts, such as woolly mammoths and saber-toothed tigers, disappeared from Eurasia, he said.
For whatever reason, the already small populations belonging to the M
haplogroup were not able to survive these changes in their habitat, and a
new population, carrying the N subtype, replaced the M-group ice-age
holdout, the researchers speculate.
Exactly where these replacements came from is still a mystery. But one
possibility is that the newer generation of Europeans hailed from
southern European refugia that were connected to the rest of Europe once
the ice receded, Posth speculated. Emigrants from southern Europe would
also have been better adapted to the warming conditions in central
Europe, he added.
Published:
15:00 EST, 1 February 2016
| Updated:
19:11 EST, 1 February 2016
ns have been blamed for killing off the Neanderthals around 30,000
years ago by breeding with them and even murdering them.
But now experts believe it was our ancestors' artistic and innovative abilities that ultimately led to the Neanderthal's demise.
The
experts believe our more advanced lifestyle gave us a cultural and
competitive edge over our ancient cousins and this paved the way for
their extinction.
+6
Experts believe Neanderthals (model
pictured right) were wiped out by artistic and innovative modern
humans. The study claims our more advanced lifestyle gave us a cultural
and competitive edge over our ancient cousins which ultimately paved the
way for their extinction
Researchers
from Stanford University in California and Meiji University in Japan
used computer models to show a small modern human population was capable
of displacing a larger Neanderthal one, if they had a sufficiently
large cultural advantage - such as artistic capability.
The
Neanderthals faced a vicious circle because as modern humans' cultural
advantages increased, their competitive advantage also increased, which
in turn further boosted their cultural advantage.
The
results, published in the journal Proceeding of the National Academy of
Sciences, add to a growing body of evidence, that modern humans
destroyed the Neanderthals.
HOW ART GAVE OUR ANCESTORS THE EDGE OVER NEANDERTHALS
Research
has shown cultural life became increasingly important for humans with
childhoods becoming longer than those of Neanderthals, for instance.
Neanderthal
children's teeth grew more quickly than modern human children, meaning
they must have had a much reduced opportunity to learn from their
parents and clan members.
Experts
believe our ancestors then moved from a primitive 'live fast and die
young' strategy to a 'live slow and grow old' one - making humans one of
the most successful organisms on Earth.
Elsewhere,
modern humans gained new cultural abilities that allowed them to better
exploit their environments and out-compete groups such as Neanderthals.
Archaeologists
have found cave paintings, rock art and beads dating from after 50,000
years ago, where before then there was limited evidence of art and
culture.
The
study explains art is an indicator of humans' ability to innovate, and
once people start innovating, technology changes rapidly.
It was likely this process that allowed humans to successfully populate the planet.
Professor
Marcus Feldman, of Stanford University in California, said: 'Most
archaeologists argue the advantage to modern humans lay in a higher
culture level, but a sizable minority dispute this view.'
He
continued that competition between the two species may have occurred
when a modern human entered a region occupied by a larger Neanderthal
population.
Professor Feldman said: 'We present a model for this replacement.
'Our
findings shed light on the disappearance of the Neanderthals, showing
that endogenous factors such as relative culture level, rather than such
extrinsic factors as epidemics or climate change, could have caused the
eventual exclusion of a comparatively larger population by an initially
smaller one.'
Research
has shown cultural life became increasingly important for humans with
childhoods becoming longer than those of Neanderthals, for instance.
Neanderthal
children's teeth grew much more quickly than modern human children,
meaning they must have had a much reduced opportunity to learn from
their parents and clan members.
Professor
Feldman believes our ancestors moved from a primitive 'live fast and
die young' strategy to a 'live slow and grow old' one - making humans
one of the most successful organisms on the planet.
This means Neanderthals, who lived in small populations across Europe, were ill-equipped to deal with the newcomers.
+6
The researchers said: 'Our findings
shed light on the disappearance of the Neanderthals, showing that
endogenous factors such as relative culture level, rather than such
extrinsic factors as epidemics...could have caused the eventual
exclusion [of Neanderthals]' A Neanderthal skull is pictured above
+6
Modern humans gained new cultural
abilities (a cave painting from Montignac, France is pictured) that
allowed them to better exploit their environments and out-compete groups
like Neanderthals. The study explained art is an indicator of humans'
ability to innovate, and once people start innovating, technology
changes rapidly
Elsewhere,
modern humans gained new cultural abilities that allowed them to better
exploit their environments and out-compete groups such as Neanderthals.
In
particular, archaeologists have found evidence that big changes
occurred in human society around the time the Neanderthals disappeared.
+6
Researchers believe the artistic and inventive attributes
(illustrated) of modern humans led to us out-competing Neanderthals
These include cave paintings, rock art and beads dating from after 50,000 years ago.
Before then there was limited evidence of art and culture.
The
study explained art is an indicator of humans' ability to innovate, and
once people start innovating, technology changes very rapidly.
It was likely this process that allowed humans to successfully populate the planet.
However,
the study will prove controversial because jewellery thought to have
been made by neanderthals up to 130,000 years ago has previously been
earthed.
Eight
talons taken from a white-tailed eagle found at Neanderthal site in
Krapina in Croatia were used to create a necklace or bracelet.
And
last year, experts claimed weapons used by modern humans were no better
than the Neanderthals' handiwork, signifying our direct ancestors were
not technologically superior.
Dr
Seiji Kadowaki, first author of this earlier study from Nagoya
University, Japan, said: 'We're not so special, I don't think we
survived Neanderthals simply because of technological competence.'
Early modern humans expanded the geographic area they inhabited out of Africa during a period of 55,000 to 40,000 years ago.
The
researchers studied stone tools that were used by people in the Early
Ahmarian culture and the Protoaurignacian culture, living in south and
west Europe and west Asia around 40,000 years ago.
They used small stone points as tips for hunting weapons like throwing spears.
Researchers
previously considered these to be an important innovation - one that
helped the humans migrate from west Asia to Europe, where Neanderthals
were living.
+6
Previously, researchers studied stone
tools that were used by
people in the Early Ahmarian culture and the
Protoaurignacian
culture, living in south and west Europe and west Asia
around
40,000 years ago. They found the human tools (pictured)
were no
more effective than Neanderthal-created tools of the same era
However, the research revealed a timeline that doesn't support this theory.
If the innovation had led to the migration, evidence would show the stone points moving in the same direction as the humans.
But
the study showed the possibility that the stone points appeared in
Europe 3,000 years earlier than in the Levant, a historical area in west
Asia.
'We
looked at the basic timeline revealed by similar stone points, and it
shows that humans were using them in Europe before they appeared in the
Levant - the opposite of what we'd expect if the innovation had led to
the humans' migration from Africa to Europe,' said Dr Kadowaki.
'Our
new findings mean that the research community now needs to reconsider
the assumption that our ancestors moved to Europe and succeeded where
Neanderthals failed because of cultural and technological innovations
brought from Africa or west Asia.'
They believe the timings imply several new scenarios about the migration of modern humans into Europe.
NEANDERTHALS WERE KILLED OFF BY MODERN DISEASES, EXPERTS CLAIM
In
April last year, scientists claimed it may have been infectious
diseases carried by our modern human ancestors as they migrated out of
Africa that finished the Neanderthals off.
Experts
studying genetic, fossil and archaeological evidence said that
Neanderthals suffered from a wide range of diseases that still plague us
today.
They
have found evidence that suggests our prehistoric cousins would have
been infected by diseases such as tuberculosis, typhoid, whooping cough,
encephalitis and the common cold.
But
anthropologists from Cambridge University and Oxford Brookes University
said that new diseases carried by modern humans may have led to the
downfall of Neanderthals.
+6
A previous study said Neanderthals may
have succumbed to infectious diseases carried to Europe by modern
humans as they migrated out of Africa. Bacteria that cause tuberculosis
are shown above
They
speculate that pathogens like Heliocbacter pylori, the bacteria that
causes stomach ulcers, were brought to Europe by modern humans from
Africa and may have infected Neanderthals, who would have been unable to
fight off these new diseases.
However,
Neandethals may have also helped modern humans by passing on slivers of
immunity against some diseases to our ancestors when they interbred.
Dr
Simon Underdown, a principal lecturer in anthropology at Oxford Brookes
University and co-author of the study, said: 'As Neanderthal
populations became more isolated they developed very small gene pools
and this would have impacted their ability to fight off disease.
'When Homo sapiens came out of Africa they brought diseases with them.
'We
know that Neanderthals were actually much more advanced than they have
been given credit for and we even interbred with them.
'Perhaps the only difference was that we were able to cope with these diseases but Neanderthals could not.'
WASHINGTON—Around 50,000 years ago, anatomically modern humans
shacked up with some Neanderthals—and the genetic consequences are still
doing a walk of shame through our generations.
The questionable interbreeding left traces of Neanderthal DNA
that are linked to mood disorders, mostly depression, as well as
tobacco-use disorders, skin conditions, and hypercoagulation (excessive
blood clotting), according to a new study published Thursday in Science.
The findings lend support to the theory that our past hominin hook-up
has had a lasting influence on modern humans’ health. The data also
offers hints at genetic adaptations of our ancient ancestors and,
potentially, new insights into the diseases they help cause in modern
humans, the authors suggest.
Having these traces of Neanderthal DNA doesn’t “doom us” to having
these diseases, cautioned John Capra, bioinformaticist at Vanderbilt
University and coauthor of the study. The genetic traces linked to
disease in modern humans doesn’t mean that Neanderthals were stricken
with those diseases either, he added. In fact, some of them could have
been advantageous.
For instance, excessive blood clotting can result in strokes and
heart attacks in modern humans. However, quick clotting is also a
natural defense against bacteria entering a wound site, Capra explained.
He hypothesizes that some of the Neanderthal traces that linger in
modern humans may have been advantageous at one point. This would make
sense, since the Neanderthals were likely highly adapted to their own
environments, he added. “Perhaps spending a night or two with a
Neanderthal is a relatively small price to pay for getting thousands of
years of adaptations,” Capra said.
Researchers have hypothesized for some time that Neanderthal DNA—the
bits that have been maintained in modern humans’ genomes, that is—can
influence health. After all, Eurasian genomes contain about 1.5 to 4
percent Neanderthal DNA. But proving that the tiny fragments of ancient
DNA has influence has been tricky.
For the study, Capra and colleagues harvested genetic and disease
incidence data from the electronic health records of more than 28,000
adults of European ancestry. Next, the researchers compared the genetic
data with that of Neanderthal genomes, looking for genetic fingerprints
of the ancient hominin’s DNA in modern genomes. Then they looked for
links between the presence of Neanderthal DNA and disease incidence in
the adults. Capra and colleagues found a number of links, some of which
seemed to be associated with sunlight exposure, they speculated. The
researchers found Neanderthal DNA variations associated with skin
conditions, including actinic keratosis, precancerous skin lesions
linked to over exposure to the sun. There were also Neanderthal links to
depression, a mood disorder that can in some cases be linked to sun
exposure in modern humans, the authors point out.
Less clear, however, was the link to tobacco-use disorders, which was
found in the analysis. It’s unlikely that Neanderthals were taking
smoke breaks 50,000 years ago outside their caves, Capra said. But the
genetic hitch in modern humans in their modern environments may confer a
complex neurological trait that now creates a predisposition to
nicotine addiction. Studying the link further could offer new
information on understanding and even treating addiction in humans,
Capra explained.
Moving forward, Capra expects that more research using big genetic
and disease datasets will reveal more ancient fragments of our genome
and their influence on health. After all, he said, human’s family tree
is a lot more bush-like than tree-like. Science, 2015. DOI: 10.1126/science.aad2149 (About DOIs).
If you sneeze when flowers bloom in the spring and tear up in the presence of a cat, your Neanderthal DNA may be to blame.
About
2% of the DNA in most people alive today came from trysts between
ancient humans and their Neanderthal neighbors tens of thousands of
years ago, recent studies have shown. Now, scientists are trying to
determine what, if any, impact that Neanderthal genetic legacy has on
our contemporary lives.
In a pair of papers published this week in the American Journal of
Human Genetics, two research teams report that in many people, a group
of genes that govern the first line of defense against pathogens was
probably inherited from Neanderthals.
These same genes appear to
play a role in some people’s allergic reaction to things like pollen and
pet fur as well, the scientists said. See the most-read stories in Science this hour >>
“It's a bit speculative, but perhaps this is some kind of trade-off,” said Janet Kelso, a researcher at the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and senior author of one of the new studies.
“Increased resistance to bacterial infection was advantageous, but may
have resulted in some increased sensitivity to non-pathogenic
allergens.”
About
50,000 years ago, the modern humans who left Africa encountered
Neanderthal settlements somewhere in the Middle East, scientists
believe. On some occasions, these meetings led to couplings whose legacy is apparent in the genomes of people with ancestors from Europe and Asia.
Not everyone with Neanderthal DNA inherited the same genes. But the immunity genes appear to be more popular than others.
Among
some Asian and European populations, the researchers found that these
particular Neanderthal genes can be found in 50% of people.
“That's huge,” said Lluis Quintana-Murci, an evolutionary geneticist at the Pasteur Institute in Paris and senior author of the other study. “It came as a big surprise to us.”
The
findings imply that these Neanderthal genes must have served our
ancestors well if they are still hanging out in our genome today, and
especially at such high frequency, said Peter Parham,
a professor of microbiology and immunology at Stanford School of
Medicine. If the DNA weren’t valuable, it would have been flushed out of
the human gene pool.
“It suggests there was a benefit for the
migrating modern human and the archaic human to get together,” said
Parham, who wasn’t involved in the research. “What has survived is a
hybridization of those populations.”
Both
of the research groups report on a cluster of three genes — known
collectively as TLR6-TLR1-TLR10 — that make up part of the body's innate
immune response to invading bacteria and viruses.
The innate
immune response is different from the acquired immune response that we
get through exposure to pathogens, either through vaccines or simply
getting sick. Innate immunity kicks in first, and if it’s successful, it
can destroy a pathogen in a few hours, before we even know we are sick.
Because
this innate immune response is so useful, it has been a strong site of
positive selection over time, Quintana-Murci said.
Though both
groups of researchers came to the same conclusion that Neanderthal DNA
plays an important role in immunity, the teams were asking different
questions at the outset of their studies.
Quintana-Murci's group
is trying to understand how microscopic pathogens have influenced the
human genome as our species has evolved.
Because infectious
diseases have killed so many people throughout human history, it makes
sense that genes involved in immunity would spread through natural
selection.
For
their new study, Quintana-Murci and his colleagues examined 1,500
innate immunity genes in people and matched them up with a previously
published map of the Neanderthal DNA in the human genome.
The team
calculated the percentage of Neanderthal DNA in innate immunity genes
as well as in other genes. When they compared them, they saw that innate
immunity genes had much higher proportions of Neanderthal sequences.
Kelso's
group, on the other hand, is interested in ancient genomes like those
of Neanderthals. In particular, her team aims to uncover the functional
consequences of long-ago interbreeding between modern humans and
Neanderthals.
The Max Planck Institute scientists analyzed the
genomes of thousands of present-day people from all over the world,
looking for evidence of extended regions with high similarity to the DNA
of Neanderthals. Then they checked how often they saw those
Neanderthal-like DNA sequences in humans alive today.
“What emerged was this region containing three genes involved in the innate immune system,” she said.
Both
research groups said there is still much work to be done to determine
exactly how this Neanderthal DNA helped humans survive.
However,
they are already certain that interbreeding with Neanderthals aided
early humans as they faced new dangers after leaving Africa.
“The
things we have inherited from Neanderthals are largely things that have
allowed us to adapt to our environment,” Kelso said. “This is perhaps
not completely surprising.”
Because Neanderthals had lived in
Europe and western Asia for about 200,000 years before modern humans got
there, they were probably already well adapted to the local climate,
foods and pathogens. Join the conversation on Facebook >>
“By interbreeding with these archaic people, modern humans could then acquire some of these adaptations,” Kelso said.
Parham
of Stanford said the results are convincing, especially since they were
made by two independent groups that essentially confirmed each other.
The results add to a growing body of work that highlights our debt to our Neanderthal relatives.
“We're right in the beginning,” Parham
said. “This type of work has really lit a fire beneath archaeologists to
try to find more and more samples of Neanderthals so geneticists can do
more population studies.”
![The researchers said: 'Our findings shed light on the disappearance of the Neanderthals, showing that endogenous factors such as relative culture level, rather than such extrinsic factors as epidemics...could have caused the eventual exclusion [of Neanderthals]' A Neanderthal skull is pictured above](http://i.dailymail.co.uk/i/pix/2016/02/01/15/30C9126000000578-3426706-Professor_Feldman_said_Our_findings_shed_light_on_the_disappeara-a-163_1454342202008.jpg)
