There are over 50,000 people in North America who define themselves as Hutterites, though you probably have never met one. One of the main branches of the Anabaptists, Hutterites live in self-sustaining communities throughout the rural northwestern United States and Canada.

Like their sister branches, the Amish and the Mennonites, the history and culture of the Hutterites have long fascinated scholars. But there have been few forays into the genetics of this unique community — until now. In the October 21 issue of the European Journal of Human Genetics, geneticist Irene Pichler and an international team of experts set out to unravel the genetic history of the Hutterites.

The history of the Hutterites goes back over 500 years, to a stretch of land in northernmost Italy called Tyrol. It was here that a small group of people, led by local hatmaker Jakob Hutter, formed a religious community centered on absolute pacificism and communal living. The Hutterites, as they came to be known, were part of the Radical Reformation, which rejected the teachings of both the Roman Catholic Church and the more moderate Protestant movement.

Due in no small part to their adherence to pacificism, the Hutterites soon became victims of persecution and expulsion. They moved several times to new settlements in central and eastern Europe. Their numbers dwindled significantly. By 1755, only 67 Hutterites were living in Transylvania.

By 1874, the Hutterites had had enough, and over 1,200 departed Europe for the rich farmland of western North America. They settled in present-day South Dakota, setting up several colonies. Today they are living much as they were upon their arrival in both the United States and Canada.

The Hutterites’ distinct and well-documented history over the past several centuries could make for an equally unique genetic history. Would traces of their history be etched in their genes? This is exactly what Pichler and her team sought to find out.

Pichler’s team focused on two segments of the human genome: the mitochondrial DNA and the Y chromosome. Because mitochondrial DNA (mtDNA) is passed down along the mother’s line, and the Y chromosome is passed down along the father’s line, the team could use both to paint a detailed picture of the Hutterites’ genetic history. The research team also analyzed DNA from several Central European groups for comparison, as central Europe is the Hutterites’ ancestral home.

Pichler proposed that the same constant reductions in population size that continually plagued the Hutterites, must also show up in their DNA. And that is exactly what happened. Among all the Hutterite DNA samples analyzed, the authors found only 11 distinct types of mtDNA (called haplogroups), and only 10 distinct Y-chromosome haplogroups. In other words, the Hutterites’ ancestral maternal and paternal lines trace back to just 21 individuals. This is an extremely small number of founders, and is further evidence that the large drops in Hutterite population size over the centuries are found in their genes.

Pichler and her team further discovered that the haplogroups among the Hutterites are vastly different from those found among central Europeans. For example, 30 percent of Hutterites belonged to a single haplogroup called X2c1 — which is virtually absent in Europe. This shows that even while the Hutterites lived in Europe, their genetics were vastly different from their non-Hutterite neighbors.

Centuries of isolation from the rest of Europe, followed by their massive migration to a new continent and continued isolation, have clearly defined the Hutterite people. And this study has revealed the history and genetics of this community as one of the most unique in North America.

Photo courtesy of Wikimedia Commons.

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About 10,000 years ago, the prehistoric hunter-gatherers of Europe began meeting some new neighbors.

These farmers spread gradually at first, expanding from the Near East through Anatolia and the Balkans. Then agriculture exploded, reaching present-day Britain within a few thousand years. The farmers settled into houses, which soon evolved into villages, towns and eventually cities.

The archaeological record tells us that much. But what it doesn’t reveal is how agriculture spread. Did it spread like a fad, as hunter-gatherer groups saw what their neighbors were doing and imitated their ways? Or was it more of an invasion, with subsequent generations of farmers advancing across the continent and overwhelming indigenous hunter-gatherer populations as they went?

Some genetic studies suggest the former. But in the September 3 issue of Science, the first study to directly compare ancient DNA (aDNA) from prehistoric burials of hunter-gatherers to that their agricultural neighbors suggests migrants spread farming through Europe.

The research team, led by Barbara Bramanti of Mainz University, sequenced the mitochondrial DNA (mtDNA) of just under 50 individuals unearthed from various prehistoric burial sites across central and eastern Europe. Half the individuals came from hunter-gatherer societies, and the other half from communities based around farming. As a comparison, they also sequenced the mtDNA of nearly 500 modern Europeans from the same parts of Europe.

The authors’ first task was to compare the hunter-gatherer mtDNA to that of the farmers. Upon doing so, they found both groups to be so different from each other that there is no way the two could be closely related. There was absolutely no overlap in the kinds of mtDNA lineages – known as haplogroups – between the hunter-gatherers and the farmers. This stark difference suggests the earliest farmers were not related to the hunter-gatherers, and most likely came to the region by migration.

And how do these two groups compare to the modern-day Europeans? The hunter-gatherers had little in common with modern people. Haplogroup U, the most common lineage among the hunter-gatherers, is one of the least common haplogroups among modern Europeans.

But the authors also found little to connect the farmers to modern Europeans. Other studies have pointed to a substantial genetic component from the Near East among Europeans, but the authors found many genetic differences between the two groups.

Based on these results, the authors have proposed an alternative theory. The unexplained component to the genetic make-up of modern Europeans may be explained by later migrations that post-date the skeletal remains examined here. It could have been a later expansion of farmers from the Near East, or perhaps an influx of hunter-gatherers from the west. The exact details remain unclear, but the authors are confident that, with additional DNA analysis, they can hope to unravel the increasingly complex story of the peopling of Europe.

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In 1974, scientists digging in the dry lake bed of Lake Mungo in southeastern Australia uncovered the skeleton of a man preserved in the deep layers of sand and clay. Dating techniques eventually revealed that this individual died about 40,000 years ago.

Scientists and the popular press dubbed the individual “Mungo Man.” Why did he make such a splash?  Not only because he was – and remains – one of the oldest and most complete skeletons of the earliest Australians, but because his appearance shattered the previously held notion that humans had first set foot in Australia less than 10,000 years ago. It was so far from where humans arose in Africa, and so remote.  So of course humans arrived there so much later than everywhere else, many experts reasoned. With the discovery of Mungo Man, this idea lost support, and scientists now concede that Australia was settled much earlier than many other parts of the world, including the Americas and parts of Europe.

While this discovery initially answered many questions regarding the peopling of Australia, it left many more unanswered — especially how people could have reached an island continent so soon after humans first expanded beyond Africa about 60,000 years ago.

The thinking is that after leaving Africa, one or more groups of humans journeyed from their homeland in East Africa into Arabia via the Red Sea. Over the next several thousand years, their descendants continued along the coasts of Arabia and India, eventually heading south into present-day Indonesia and finally to Australia, which was joined with the island of New Guinea at the time.

There has been some archaeological and genetic evidence of such a migration, but most of it has been indirect or circumstantial. Some scientists remain unconvinced because researchers have not been able to show a direct link between modern Australian Aborigines and modern people living along the coastal route from Africa. But now, in a new study led by the Anthropological Survey of India, geneticists believe they’ve found the first concrete evidence of such a link. Their results are reported in the July 21 issue of BMC Evolutionary Biology.

The team, led by Satish Kumar, reasoned that if the hypothesis of an ancient migration along the Indian Ocean coast toward Australia was accurate, there would be evidence in the DNA of modern people living along that path. So they compared the DNA of modern Australian Aborigines to that of tribes from India, such as the Baiga of central India and the Birhor of eastern India. These groups are often called “relic populations” because they are believed to share many cultural, linguistic, physical and genetic features with the region’s ancient inhabitants.

Experts have long noticed that the Baiga, Birhor and other relic populations share physical similarities with native Australians. Kumar and his team reasoned that there could be DNA similarities too.

Kumar led the extraction and analysis of mitochondrial DNA (mtDNA) from nearly 1,000 individuals from Indian relic populations. For comparison, they used Australian Aboriginal DNA data that had already been analyzed and published by colleagues. After comparing the two groups, they came to a startling conclusion: two specific genetic mutations on the mtDNA of the Indian and aboriginal samples matched perfectly. Not only that, but these particular mutations do not exist elsewhere in the world; they are shared exclusively between a few isolated tribes in India and native Australians.

Kumar and his colleagues concluded the two groups must share a common ancestry. To lend further credence to their theory, they calculated the date when the ancestors of the Indian tribes and Aborigines must have split.

Their calculations produced a date of 55,000 years ago, a time when early humans in India were probably hunting wildlife and gathering plant foods. Some of their descendants eventually formed tribes like the Baiga and Birhor; others moved eastward, traversing southeastern Asian and then using maritime technology to cross nearly 60 miles of open ocean between Indonesia and New Guinea.

After arriving in Australia, they moved into the heart of the Australian Outback. A few thousand years later, a direct descendant of these ancient explorers was laid to rest along the shores of Lake Mungo.

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The Neanderthals have always held a special place in the field of anthropology.  The skeletal remains of our short, stocky evolutionary relatives have been found everywhere from Spain to Iraq.

Their physical likeness to our own species, and the possibility that humans and Neanderthals may have interacted, has long fascinated experts and enthusiastic novices alike.  But simply studying their skeletal remains and artifacts seemed to leave more questions than answers.

More than 10 years ago an international team of scientists became the first to extract and analyze ancient DNA (aDNA) from a Neanderthal skeleton. By examining the mitochondrial DNA (mtDNA) — which is more abundant in our cells than our nuclear DNA and therefore more likely to preserve — they found that there were enough genetic differences between this Neanderthal and modern humans to classify the two as separate species.

Since this initial foray into Neanderthal genetics there have been attempts to improve aDNA analysis, with the goal of filling in the gaps that traditional anthropological techniques had been unable to.  Earlier this year, scientists at the Max Planck Institute for Evolutionary Anthropology became the first to sequence the entire Neanderthal mitochondrial genome – no easy feat. Now scientists have taken aDNA analysis to the next level by developing a novel technique to extract it more easily, yielding the most comprehensive and accurate results to date.  Along the way, they have uncovered some intriguing clues to the possible fate of the Neanderthals. Their results are reported in the July 17 issue of Science.

This new study, also led by Max Planck Institute scientists, centers around a novel method for finding and extracting that elusive aDNA from Neanderthal remains. The study took advantage of a new kind of aDNA extraction process, called Primer Extension Capture (PEC). This technique has many advantages over the others, primarily because it allows the aDNA to be completely isolated from all the other molecular junk  that can accumulate over time. This yields highly accurate results with much less effort. So instead of simply using this technique on one Neanderthal individual, they analyzed five.

The remains they chose had been excavated from a variety of locations, from Croatia to Germany to Spain and Russia.  Most of the remains were between 35,000 and 40,000 years old, which is very close to when Neanderthals were believed to have disappeared from most of their range.  They also examined Neanderthal remains from Russia that dated to between 60,000 and 70,000 years old.

After successfully extracting and analyzing the DNA of these remains, the researchers came to a few startling conclusions.  First, the level of genetic diversity among the samples was exceedingly low.  In fact, the amount of genetic diversity of the Neanderthal samples was less than one-third the diversity we see in modern humans today. For example, two of the samples — one from Croatia and the other from Germany — had identical mtDNA genomes. For two individuals living nearly 1,000 miles apart, this is quite unusual; unless there wasn’t much variation in mtDNA in the first place.

The authors of this report think this genetic homogeneity means that there were far fewer Neanderthals living in Europe and western Asia than they’d previously thought. Based on their analysis of the five individuals, the they estimated that the total population size of Neanderthals in Europe 35,000 years ago may have had as few as 3,500 females (because mtDNA is passed down maternally, it cannot be used to estimate male population size).

The authors believe there are two possible explanations for this small population size.  The first is that, over the 400,000 year history of Neanderthals, their population may have always been small.  After all, for much of their existence they survived harsh ice age conditions, so low population size may have been necessary for survival.

But the authors offer an alternate explanation as well. They think this small population size is the result of long-term population decline, perhaps beginning about 40,000 years ago and continuing until Neanderthals were wiped out. To test their hypothesis, the researchers re-analyzed the Neanderthal mtDNA genomes and found that their protein-encoding genes had evolved much more quickly than those of humans or chimpanzees since the three species split, millions of years ago.

This high rate of evolution, the authors argue, was not present in the older Russian Neanderthal sample.  This fact implies a pattern of decline in population size, not a population that had been small from the start. These results support their idea that the Neanderthal numbers were on the decline.  Without direct evidence, they can only speculate as to the cause of of their decline, but the scientists believe it may be tied to the arrival of humans in Europe and western Asia about 40,000 years ago.

Today most experts believe the Neanderthals were being out-competed by the incoming humans, who had superior technology and language skills.  Over time, the Neanderthals were forced to move to more isolated regions in the mountains of France and Spain.  By 30,000 years ago, only a few traces remained.  Soon after, they were gone.  This study reveals some compelling evidence that humans were in fact responsible – whether directly or indirectly – for the demise of the Neanderthals.

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Nicolaus Copernicus is probably the second most famous astronomer in history (after Galileo). He is best known for being the first to propose that the Earth circles the sun, and not the other way around.

His theory ran into one problem, however. It was contrary both to conventional wisdom and Roman Catholic Church doctrine. So even though Copernicus had written his book on the subject, De revolutionibus orbium coelestium, he declined to publish it until he lay on his deathbed in 1543 to avoid eliciting unpleasant criticism from the Church.

It turns out that Copernicus was right — and not just about the solar system. De revolutionibus met with harsh criticism over the next few hundred years.  Finally, in 1835, it was dropped from the Church’s Index of Prohibited Books, where it had been for more than two centuries.

Today, Copernicus is honored as a scientific titan. Since 1833, admirers have been able to pay homage to him in the Polish city of Warsaw. But they couldn’t visit his grave; until recently, no one could find his body.

It was known that Copernicus lies somewhere in the crypt of the cathedral in Frombork, Poland, where he lived for most of his life. But there are hundreds of other individuals interred there as well. Most of their tombs are unmarked, making identification extraordinarily difficult.

For decades archaeologists have been trying to narrow down which skeleton belonged to that of the 16th century astronomer.  Recently, researchers in Poland and Sweden decided to turn to the field of ancient DNA analysis to solve this mystery.  Their results are summarized in the Proceedings of the National Academy of Sciences: USA.

Prior to the DNA analysis, anthropologists had performed digital facial reconstruction on many of the crypt’s skulls, in hopes that one might bear a distinct resemblance to paintings of Copernicus. In 2004, Polish scientists found a candidate.  But without more convincing evidence, they could not verify the skeleton’s identity.

This is where ancient DNA analysis comes in.  Even though DNA begins degrading immediately following death, the genetic material is often preserved in the teeth for hundreds or thousands of years. Scientists studying ancient DNA (aDNA) usually focus on the type of DNA that has the greatest chance of surviving: mitochondrial DNA (mtDNA), which is passed exclusively from mother to children. The sheer abundance of mtDNA makes it much more likely to survive; each cell contains hundreds of copies.

Yet even after successfully extracting mtDNA from the skeleton’s teeth, one problem remained: the researchers had no DNA for comparison. They needed to find a DNA sample from Copernicus, or one of his descendants, in order to confirm these were in fact his remains. They found that sample in a seemingly unlikely place, housed inside a copy of the 16th century astronomy reference book Calendarium Romanum Magnum. This copy was of particular interest firstly because it was the personal copy of Copernicus himself, and secondly because there were hairs stuck within the binding that the scientists hoped contained his DNA. So the researchers analyzed DNA from the hairs, hoping that both they and the teeth had preserved enough DNA for analysis.

Their hopes were realized when both teeth and hair produced definitive mtDNA profiles that matched exactly. Both belonged to haplogroup H, a branch of the human mitochondrial genetic tree that is common across Europe. These results were verified independently at three laboratories, so the possibility of contamination is minimal. Because the two DNA samples were an exact match – with not even a single letter of DNA code out of place – the researchers conclude that the skeleton  whose facial features so much resembled Copernicus had to be that of the famous astronomer.

But now that they knew his identity, these authors decided to run one more analysis on Copernicus’ remains.  They were able to study a particular genetic marker, or SNP, found in the gene HERC2 that is believed to play a role in determining eye color. The authors found that Copernicus had a version of the SNP that predisposed people to a light eye color, such as blue or gray.  This is quite intriguing, as almost all paintings of the astronomer show him with dark brown eyes.

(23andMe also uses SNPs in the HERC2 gene for our Health and Traits report on Eye Color.  Current 23andMe customers can see their most likely eye color based on the HERC2 gene here.)

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Not many people could survive the harsh conditions of the Sahara Desert.  Yet the Tuareg have lived in the the region for millennia.

The Tuareg call themselves the Imazghan, meaning “free people.” Today they are known for a distinctive dark blue turban worn by the men, and for their long history as gatekeepers of the Sahara Desert. They are a semi-nomadic people who inhabit the West-Central Sahara, which encompasses parts of western Libya, Algeria, Mali, Niger, and some neighboring countries.

The Tuaregs were first mentioned by the ancient Greek historian Herodotus, who spoke of a group known as the Garamantes living in the Fezzan region of southwest Libya that operated trans-Saharan trade routes, connecting the heart of Africa to the North African coast. It is now believed that he was speaking of the Tuareg.

Though known to scholars since Herodotus’ depiction thousands of years ago, the Tuaregs remain shrouded in mystery. Their extreme isolation in one of the earth’s harshest environments has made them difficult for cultural anthropologists to study.  There have been only a handful of studies published on the Tuaregs’ genetic history, and even these examined only the genetics of western Tuaregs from Mali, Niger and Nigeria. The eastern Tuaregs who inhabit the Fezzan of Libya remain far less studied.  So a team of scientists decided to rectify this lack of genetic data, analyzing the mitochondrial DNA (mtDNA) of more than 100 Tuaregs from the Fezzan region of Libya. Their results are reported in the July issue of Annals of Human Genetics.

The authors chose to analyze the mtDNA for a variety of reasons, but mostly as a way of comparing their results to the previous genetic studies that had also used mtDNA. After extracting the DNA of the Tuaregs and assigning each individual to a specific maternal ancestry branch, or haplogroup, they found that the majority of Tuaregs fell into the same haplogroup: H1. In fact, over 61% of the individuals bore haplogroup H1.  This piqued the researchers’ interest, mainly because H1 is often thought to have spread with people from the Iberian peninsula across Europe after the end of the Last Ice Age about 12,000 years ago. The results of this study indicate that somehow H1 must have traveled into North Africa as well.

Not only did the researchers find that so many Tuaregs bear the same maternal haplogroup, but there was low genetic diversity among the population overall. This low genetic diversity can be tied to the fact that the Tuaregs are a very isolated people, and it is uncommon for them to venture too far outside their community when looking for a spouse. Indeed it seems that these Libyan Tuaregs are even genetically isolated from their West African counterparts, who showed far less European ancestry and far more ancestry tracing back to sub-Saharan Africa, despite the fact that both eastern and western Tuaregs share a common language and culture.

The authors have used these bits of information to piece together a scenario for the origins of the Libyan Tuaregs.  Environmental data reveal that, about 5,000 years ago, the Sahara was quickly shifting from its post-Ice Age period of relative stability and good living conditions to a less stable and more arid environment. This shift, the authors propose, was responsible for a series of human migrations throughout the Sahara that led different Tuareg groups living in the region to separate.  It caused other Tuareg groups to intermingle with neighboring groups.  Some Tuaregs, like those in Mali, Niger, and Nigeria, probably had more contact with sub-Saharan West Africans, which accounts for the higher percentage of sub-Saharan maternal haplogroups found by previous genetic studies.  Others, like the Libyan Tuaregs analyzed here, may have met and mingled with groups such as the Berbers of the Mediterranean coast of North Africa.  Apparently migrations from Spain after the Last Ice Age, across the Strait of Gibraltar into Morocco, brought H1 into the African continent. It then made its way into the North African Berber populations, eventually finding its way into the Libayan Tuaregs.

And what of the 35% of Libyan Tuaregs with sub-Saharan African genetic ancestry?  The authors of this study believe this to be a genetic signature of the trans-Saharan slave trade, which the Libyan Tuaregs famously operated during the 1st century BC, and which brought them to the attention of Herodotus so many years ago.

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Only 250 miles separates the island of Madagascar from the southeast coast of Africa.  The short distance between the two land masses traditionally led the outside world to assume that the native inhabitants of Madagascar – known as the Malagasy – originally came from the west, probably from the present day southeast African nation of Mozambique.  Yet upon closer examination of the Malagasy’s language and their physical features, many scholars began to question this notion.  The Malagasy of the central plateau of Madagascar, known as the Highlanders, had light skin and facial features more akin to Southeast Asia or Indonesia.  They also practiced a rice culture that was not unlike the rice cultures of Asia.  And yet the coastal Malagasy, known as the Côtiers, seemed just the opposite.  They had darker skin and curly hair that was more similar to modern day Africans.

But both the Highlanders and the Côtiers speak the same language, which shares 90% of its vocabulary with a language spoken today in Southeast Borneo, and which has been officially classified as a branch of the Austronesian language family called West Malayo-Polynesian.  So how could a significant portion of Malagasy seem to share more in common with a region 5,000 miles away than they do with mainland Africa?  Trying to find the answers to these questions has vexed archaeologists, historians and linguists for generations.  Over the past several years, geneticists have entered the fray to try and unravel the mysterious origins of the Malagasy.  Their most recent effort appears this week in Molecular Biology and Evolution.

This study, led by Sergio Tofanelli of the University of Pisa, built upon a 2005 study by Matt Hurles and colleagues that was the first genetic exploration of the Malagasy people.  But Tofanelli and his colleagues wanted to dig even deeper into the genetic history of the Malagasy.  So they took the data analyzed by Hurles in addition to new DNA samples that were collected from people across the island of Madagascar.

They focused on two regions of the human genome often used in genetic ancestry studies:  the mitochondrial DNA (mtDNA) and the Y chromosome.  Because the mtDNA is used to trace maternal ancestry, and the Y chromosome to trace paternal ancestry, analyzing both in the same study can give a more complete picture of a group’s genetic history.

Tofanelli and his research team examined the mtDNA and Y chromosomes of Malagasy individuals scattered across the island, from both the Highlander and Côtiers groups.  They were searching for any clues that would give an exhaustive understanding of how and when the island of Madagascar was first settled, and by whom.

The researchers’ analysis revealed a mixture of both African and Asian genetic ancestry, in both the Highlanders and the Côtiers, which is perhaps contrary to the two groups’ physical apperance.  So what does this mean?  That even the Côtiers people, who often look more African in appearance, have an ancestry that traced back to Asia, specifically Borneo.  These results fit well with Hurles’ study and with what linguists have been saying for years; that the Malagasy language – while clearly tracing back to Borneo – also has some African elements that are significant.

The results from these analyses then begged the next question — how and when did the earliest inhabitants of Madgascar arrive on the island?  Was it in two separate migrations – one from the east and one from the west – or did the Asian/African genetic make-up of the Malagasy exist prior to their first steps on Madagascar?  It is easy to assume that any intermarriage between Africans and Southeast Asians happened after each arrived on the island.  In fact, Tofanelli describes the genetic make-up of the Malagasy as a consequence of “the encounter of people surfing the extreme edges of two of the broadest historical waves of expansion” in human history.  He is referring to the sub-Saharan African Bantu expansions that began 5,000 years ago and swept across Africa from Cameroon to Mozambique and southern Africa, and the Austronesian expansions about 4,000 years ago when seafarers journeyed from Taiwan to Borneo and beyond.

But Tofanelli proposes an alternative hypothesis as well.  He argues for a long history of contact between Bantu-speaking Africans and seafarers from Borneo dating back thousands of years.  As evidence he cites banana cultivation in Cameroon and Uganda that can be traced back to Southeast Asia, as well as the introduction of humped cattle into Africa from Asia.  If the Southeast Asians and eastern Africans shared farming techniques, it stands to reason that they may have shared genes as well.  Thus the people of Madagascar may have not simply been Africans and Southeast Asians arriving on the island from opposite directions, but rather they represent a more complex genetic history of proto-Malagasy arriving on Madagascar about 2,300 years ago, already containing a mixture of Asian and African ancestry.

This hypothesis most certainly needs additional evidence and data before it can be supported, but it brings a new level of understanding to the mysterious origins of the Malagasy.

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Just over 20 years ago, the first study using mitochondrial DNA (mtDNA) to trace prehistoric human migrations was published. In this seminal study, scientists managed to determine that all humans alive today can trace their maternal ancestry back to one woman who lived about 200,000 years ago in Africa. The findings were revolutionary, and the idea that we could use genetics as a new tool to examine human prehistory was staggering.

One of the main reasons mtDNA was originally used was that it is passed down relatively intact, from mother to children, without recombining with any other bit of the human genome. And even more importantly, there was a small section of the mtDNA that did not code for any genes and was thus unaffected by natural selection. Any changes in this bit of mtDNA over time had to be caused by random mutations, which were believed to occur at a regular, clock-like rate. By counting and analyzing the mutations distinguishing any two individuals – or any two groups of people – scientists reasoned they could discover when their most recent maternal ancestor lived.

But there were a few problems with this idea. First, the small section of mtDNA scientists were analyzing, known as the Hyper-Variable Region (HVR), represents only about 2.5% of the entire mitochondrial genome. Some scientists argued that analyzing the genome in full would yield more accurate information about our past. Second, the idea that the mutations in our mtDNA accumulate like clockwork has been questioned continually. Just last year, 23andMe scientists reported that the mtDNA mutation rate may have been accelerating since the end of the Last Ice Age about 15,000 years ago, when human populations around the world began to grow and diversify at much faster rates. It soon seemed that many of the time estimates scientists had been calculating for years had been less accurate than previously thought.

So geneticists at the University of Leeds took decided to create a new method of calculation based on the best possible evidence. In the June 12 issue of the American Journal of Human Genetics, the team led by Pablo Soares and Martin Richards describes how they developed a way to estimate the maternal ancestry of the world’s people that is more accurate and precise.

The revised method used by these geneticists centered around the idea of natural selection. Up to now natural selection had not played a major role in calculating time estimates, mainly because scientists only used the HVR to make these calculations, which was thought to be immune from natural selection. Natural selection, an evolutionary force first described by Charles Darwin, gradually removes harmful genetic mutations and does appear to act on much of the mitochondrial genome. Failing to account for this evolutuionary force, according to Soares, has led to inaccurate and imprecise time estimates. “What we’ve done is work out a formula that corrects this effect,” says Soares. Using this newly developed mathematical formula, “we can [now] date any migration for which we have the available data.”

After developing this formula, Soares and his colleagues set about to test current theories on prehistoric human migrations patterns by comparing previous time estimates to those calculated using their new and improved formula. The results have already cleared up some problems with the previous estimates. Using their formula to calculate the time when humans first made their away across the Bering Strait to the Americas, they came up with a date of about 15,000 years, a full 2,000 years later than previous estimates. This new estimate can put to rest a longstanding discrepancy between genetic data and the archaeological record.

According to Richards, “We can settle the debate regarding mankind’s expansion through the Americas. Researchers have been estimating dates from mtDNA that are too old for the archaeological evidence, but our calculations confirm the date to be some 15,000 years ago, around the time of the first unequivocal archaeological remains.”

The 23andMe Maternal Line feature already puts that event at 15,000 years ago, because our scientists rely on both archaeological and genetic evidence when estimating the dates of past events.

Soares and colleagues found similar differences when recalculating the time estimates of other important prehistoric migration events, like the peopling of Polynesia just a few thousand years ago and the earliest migration of modern humans out of Africa nearly 70,000 years ago. But if anything, these corrections bolster the use of mtDNA in dating prehistoric events. Contrary to what some scientists have long feared, this study reveals that the principle underlying the technique was always sound; it was the specific method scientists used to analyze mtDNA that required a bit of fine-tuning.

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There are many mysteries surrounding the final days of the last Emperor of Russia, Tsar Nicholas, and his family.  The most perplexing of them all is the fate of one of the Tsar’s daughters, the Grand Duchess Anastasia.  Even after Bolsheviks  murdered the family in the summer of 1918, rumors circulated throughout Europe that Anastasia (and sometimes her brother Alexsei as well) may have escaped the slaughter.  When the remains of the Romanovs were discovered several years later, minus two of the Tsar’s children, the idea that at least one child escaped seemed much more credible.

But in 2007, these rumors were quelled when a second burial site was discovered a few miles from the first.  This grave contained the remains of two children; preliminary forensic analysis identified them as the Tsar’s son Alexsei and one of his sisters.  With the discovery of this second burial all family members, servants, and physicians who were killed that summer evening over 90 years ago were finally accounted for, or so it seemed.

Yet in spite of this new discovery, many remained unconvinced.  They called for the new remains to be scrutinized – that both the physical remains and their DNA be tested – to make certain that these were in fact the Tsar’s children.  So, an international team of scientists undertook this daunting task by examining the DNA of the children in the new burial as well as the DNA in the original burial, to finally put to rest the rumors that have persisted for so long.  The team of scientists reports their findings online this week in the Proceedings of the National Academy of Sciences.

The researchers began by extracting and sequencing the mitochondrial DNA of the skeletons in the second burial.  Because mitochondrial DNA (mtDNA) is present in great quantities in each cell of our bodies, they reasoned it would be easier to find and therefore easier to analyze.  In addition, because mtDNA is passed down from mother to children, the scientists knew that they could compare the mtDNA of these skeletons to that of their mother, the Tsarina Alexandra, who was among the skeletons in the first burial.

Upon comparing the two children in the second grave, the scientists found their mtDNA to be identical – meaning that they must be related, and probably shared the same mother.  And when they analyzed the mtDNA of the Tsarina, they found that she matched the two children from the second burial. Additional tests revealed one of the children to be a boy, and the other a girl, also lending support to the notion that one of the children was the Alexsei, and the other one of his sisters.

But the scientists did not stop there.  They decided to perform one final test.  This test centered around the remains of Tsar Nicholas, found among his family at the first burial site.  While most scholars agreed that the Tsar was among the skeletons in this grave, it had not been conclusively proven.  To tie up any loose ends, the scientists needed some method of confirming the Tsar’s idenitity.

That method came by way of a piece of clothing formerly belonging to the Tsar.  One of the Tsar’s shirts, preserved at the Hermitage Museum in St. Petersburg, was stained with some of his blood; blood that contained the Tsar’s DNA.  After examining the DNA from the blood on the shirt, the scientists found it to be an exact match to the DNA of the remains at the first burial.

Almost 91 years after their murder, Russia’s last royal family is finally all present and accounted for.

Be sure to check the Spittoon again tomorrow, when we delve deeper into the Romanov mystery and explore other puzzles in recent history that have been solved using DNA.

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At the Spittoon we love to hear how scientists are using our DNA to unlock the mysteries of our ancestors.  In fact, hardly a week goes by when we don’t report on the latest discovery in the field of genetic ancestry.

Occasionally, however, researchers manage to uncover some mystery of the human past using the DNA of another species. Take the stomach parasite Helicobacter pylori, for example, or the ever-popular louse.

Now an interdisciplinary team of scholars from North Carolina State University, led by assistant professor of English Dr. Timothy Stinson, has developed a means of using cow DNA to determine the origins of medieval manuscripts.

Traditionally, scholars rely on handwriting and subtle differences in dialect to identify the origins of medieval manuscripts, which have often proven unreliable. But there’s another clue: the parchment itself. Parchment, unlike paper, is actually made from animal skins.  From the earliest civilizations in Eygpt, Greece, and Rome, scribes often used parchment for their written records.  During the Middle Ages, the use of parchment extended to religious texts and other kinds of manuscripts.  Sheepskin, calfskin, or goatskin would be stretched thin and dried, cut into appropriate sizes, and bound together in book form.

That’s harsh treatment for a molecule as delicate as DNA. Yet when scribes prepared these strips of parchment, the DNA from the skin of the animal – be it cow, sheep, or goat, was not easily removed.  Instead, some parts of the animal’s DNA – specifically, the mitochondrial DNA, remained on the piece of parchment.  Using state-of-the-art DNA extraction technology, Stinson and his colleagues have extracted and analyzed the DNA from two 15th-century French manuscripts. Their initial goal was to test whether they could in fact retrieve any DNA at all.  If so, they hoped to learn what that DNA might tell them.

Initially, the DNA tests revealed that the pages all seemed to come from the same animal: Bos taurus, otherwise known as the domestic cow.  But when the scientists analyzed the DNA more closely, they found that the different pages of the same manuscripts each shared the same mitochondrial DNA.  Their conclusion: it’s likely that each manuscript was made of hide from the same animal (or at the very least, very closely related individuals).  This means that the pages of parchment might have been prepared around the same time, rather than pieced them together from a variety of different sources.

More than simply identifying the species of animal used in creating these pages of parchment, there are many other benefits that can be gained from DNA analysis of medieval manuscripts. Stinson hopes that genetic testing of these manuscripts can help scholars discover exactly when and where they were produced.

Soon, Stinson hopes that genetic testing of manuscripts “will also allow us to trace trade routes of parchments” throughout medieval Europe.  Traditional theories on the origins of individual manuscripts can finally be put to the test using genetic evidence, and medieval scholars would have a new tool to use when tracing the evolution of the medieval book industry.

It is clear that, just as the rise in prominence of human DNA analysis has revolutionized the fields of archaeology and anthropology, so too can the DNA analysis of medieval manuscripts revolutionize the fields of history and literature.  Dr. Stinson discusses DNA testing of medieval manuscripts at the Bibliographical Society of America in New York City on January 23.

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