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Through the millennia wave after wave of migrants &#8211; often in the form of invading armies — have descended upon the British Isles.
The first people to arrive after the Ice Age were hunter-gatherers who followed their prey north from southern Europe about 12,000 years ago. The Celts came from central Europe about 3,000 years ago. Then came the Romans, followed by the Anglo-Saxons, Vikings and finally the Normans in 1066 AD.
With each successive invasion, the previous people were either absorbed by the invaders, or retreated to the isolated corners of the Isles. Often called the &#8220;Celtic Fringe,&#8221; these regions have been studied as a window into the ancient history of the British Isles. Some scholars even propose that the present-day people of the fringe could be direct descendants of the earliest humans to arrive on the Isles after the Ice Age.
But despite exhaustive research into the history and genetics of the Celtic Fringe, its prehistory remains mysterious, forcing scientists to think outside the box. In the September 30 issue of the <a href="http://rspb.royalsocietypublishing.org/content/early/2009/09/25/rspb.2009.1422.abstract">Proceedings of the Royal Society B: Biological Sciences</a>, biologist Jeremy Searle and his research team did just that, devising an unconventional method to study the prehistoric peopling of the British Isles.
They could have examined the DNA of the Celts themselves. But that&#8217;s already been tried, so Searle and his colleagues turned their research underfoot.
Earlier analysis found similar genetic patterns in populations of both common shrews and humans inhabiting the Celtic Fringe. Using those results as a benchmark, Searle and his team expanded the genetic analysis to the pygmy shrew as well as two species of voles.
Searle reasoned that if these shrews and voles had similar immigration patterns to early humans, perhaps those patterns would show up in their DNA. Specifically, he believes that &#8220;this study can help us understand why humans in the British Isles form a Celtic Fringe.&#8221;
Interestingly, Searle and his colleagues&#8217; analysis revealed a division in DNA types for the shrews and voles similar to that separating the people of the Celtic Fringe and the rest of the British population. Further analysis revealed that the DNA types for the mammals living in the Celtic Fringe were quite old. So old, in fact, that Searle and his team propose that the arrival of these mammals traces all the way back to the post-Ice Age arrival of humans 12,000 years ago.
If the mammals living in the Celtic Fringe date back 12,000 years, the people living there could as well.
There is one problem with this hypothesis. The Celts themselves only arrived from mainland Europe 3,000 years ago, not 12,000 years ago. Conventional wisdom states that the Celtic Fringe only evolved after the Celts were pushed back following the invasion of the Romans and Anglo-Saxons.
How does Searle explain this discrepancy? He and his team argue that the Celtic Fringe is not actually Celtic in origin. Rather, its presence predates the arrival of the Celts and their arrival only &#8216;reinforced&#8217; a pre-existing division that was already there.
In that case, it would have been the Celts themselves whose arrival pushed earlier inhabitants to the isolated corners of the British Isles. Subsequent migrations would have pushed the Celts into these same corners, which is why the language and culture of these regions are inherently Celtic. And that would also explain why the languages, culture, and history of the pre-Celtic people of Britain have mostly been lost to time.

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Shrews and Voles Reveal Clues to British Prehistory

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Editor&#8217;s note: This post has been edited slightly since publication.
Many examples worldwide of two distinct ethnic groups living side by side.
Sometimes, these groups co-exist peacefully. Other times, they do not.
Differences
Often, the differences between two groups &#8211; along with circumstantial factors &#8211; lead to tension between them and sometimes violence. The Hutus and Tutsis of Rwanda, the Sunnis and Shiites of Iraq, and the Croats and Serbs of former Yugoslavia all illustrate how cultural distinctions &#8211; like language and religion &#8211; can contribute to tensions and conflict around the globe.
But do these cultural and ethnic distinctions translate to biological distinctions as well?
<h6>A Study of Differences and Similarities</h6>
Exactly how biologically distinct are two ethnic groups living side by side? Anthropologist Evelyn Heyer and an international team of researchers set out to answer these and many other questions by studying the adjacent &#8211; and culturally very different &#8211; Tajik and Turkic speakers along the Silk Road of Central Asia. Their results are published in this week&#8217;s <a href="http://www.biomedcentral.com/1471-2156/10/49/abstract" target="_blank" rel="noopener">BMC Genetics</a>.

The authors focused on the Tajik and Turkic speakers because those groups offered a unique perspective on how two groups living in such close proximity can be so different from each other.
<h6>Language and Cultural Differences</h6>
The Turks are largely nomadic herders. They speak Indo-Iranian languages like Azerbaijani, Turkish, and Altay. Their society is organized into clans, or &#8220;descent groups,&#8221; whose membership is passed down from father to children.
The Tajiks are, conversely, agriculturalists. They speak various dialects of the the Tajik, or Tajik Persian, language that may have arrived with Muslim invaders 1,000 years ago. Their society is largely patrilocal &#8211; meaning that when couples marry they put up residence near the husband&#8217;s family; and first cousin marriages are encouraged.
The two societies are supposedly closed, and members of both groups are said to rarely leave their clan or village. This cultural isolation made them perfect candidates for Heyer and her team to study.
The researchers collected maternally inherited mitochondrial DNA and paternally inherited Y chromosome DNA from more than 1,000 individuals spanning 24 Turkic and Tajik populations.
<h6>Shared Genetics</h6>
They found that, genetically, the Tajiks and the Turks were virtually indistinguishable.
Genetically, the Tajiks and the Turks were virtually indistinguishable. The authors found the overall level of genetic diversity between the two groups to be less than 1 percent—so small that there was greater diversity within each group than between the two.
Their analysis also sheds some light on the origins of these two ethnic groups. The modern-day people of Central Asia maintain their own origin stories unique to their particular group. These unique origin stories, in part, distinguish them from one another.
But Heyer&#8217;s analysis proves that these groups share the same roots; they are simply a hodgepodge of the clans, tribes, and villages that have called Central Asia their home for thousands of years. Over many generations, they banded together to form larger groups until they consolidated into just two major divisions: the Tajiks and the Turks.

A photo of people on the street in New York

New Study on Genetics of Ethnic Groups Reveals We May Not Be So Different After All

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On August 20, 79 AD, a series of small tremors and earthquakes began to shake the two ancient Roman cities of Pompeii and Herculaneum.
<h6>Vesuvius</h6>
Lying in the shadow of Mount Vesuvius – about 150 miles south of the Roman capital – the two cities were often hit by tremors and earthquakes, so most residents were unperturbed.   After all, the tremors were relatively mild, especially compared to a severe earthquake that had hit both towns 17 years earlier.
They did not know, however, that this new string of tremors was in fact due to increasing pressure inside Mount Vesuvius; they did not know that Mount Vesuvius was in fact an active volcano; and they did not know that it was about to erupt.
Just four days later, on August 24, Vesuvius did just that.   The cities of Pompeii and Herculaneum were taken completely off guard.
<h6>No Escape</h6>
So much so, in fact, that many residents were unable to escape the rain of pumice and ash that fell to dozens of meters high, burying people inside their homes.   Even those who did survive the ash were unable to outrun the pyroclastic flow, a wave of white-hot cinders that tumbled down Mt. Vesuvius at over 100 mph.   In just a few days, these cities became buried, and soon were forgotten.

Pompeii and Herculaneum remained buried for the next 1,600 years, when military engineers digging a new course for the River Samo uncovered what looked to be an underground city.   They had found the remains of the buildings, houses and plazas that made up these two ancient Roman cities.   And &#8211; perhaps more importantly &#8211; they found the remains of the inhabitants, often almost perfectly preserved.
<h6>Analyzing Remains</h6>
This was especially true for the remains of 13 individuals, hidden inside a villa belonging to a Pompeii resident named Caius Iulius Polybius.
Inside the villa, two individuals were still holding hands; another was clutching her stomach, the remains of her unborn child still inside. Archaeologists have spent many decades trying to uncover as much as possible about these and the other thousands of individuals found buried in Pompeii and Herculaneum.   Now geneticists have entered the fray, using sophisticated techniques to extract and analyze the DNA of these 13 individuals with the goal of understanding the relationships between them.   The results of this analysis are published in the July issue of the the Annals of Human Genetics.
The research team, led by Giovanni de Bernado from the University of Naples, extracted the mitochondrial DNA (mtDNA) from all 13 individuals.
The mtDNA is passed down, almost always unchanged, from a mother to her children. So researchers can conclude that individuals in a grave or archaeological site who share similar or identical mtDNA profiles &#8211; known as haplogroups &#8211; are likely related to each other along the maternal line. The mtDNA is also useful in archaeology because it is more likely to remain preserved long after an individual dies.
But there can be problems with preservation when analyzing mtDNA, and that is exactly what happened with a few of the remains.   Di Bernado and his team were unable to extract mtDNA from three of the individuals.   But for the others, they were successful.
<h6>Familial Relationships</h6>
In fact, six of the individuals yielded an identical maternal haplogroup assignment:   T2b.   T2b exists in about 4-5% of modern Italians, making it one of the rarer haplogroups in the region.   So for it to exist at such high levels within a single household almost certainly proves some kind of familial relationship between the inhabitants of this house.
Who were the individuals bearing the T2b haplogroup?   Four children ranging in age from three to 14, a young woman of about 18 years, and a man of about 30 years. Di Bernado argues that the four children were probably siblings (or at least cousins), that the 18 year-old woman could perhaps be an older sister or aunt, and the man is likely to be a maternal uncle.   Unfortunately, one of the female remains &#8211; who would be an ideal candidate as the childrens&#8217; mother, yielded no reliable mtDNA type.   The remaining individuals bore different haplogroups, and may have represented the father or paternal grandparents.   There is also the possibility that one of the adult women was a mistress of the head of the household, something not uncommon in ancient Rome.
For many years, the identities of the Pompeian and Herculanean victims&#8217; remains, entombed in ash and cinders, have both haunted and intrigued scientists.   Now, with efforts such as the ones performed here by Di Bernado and colleagues, we are learning more about who they were in life, and not just about their final moments.

Ancient DNA Analysis Reveals Family Ties in Ruins of Pompeii

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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 &#8211; known as the Malagasy &#8211; originally came from the west, probably from the present day southeast African nation of Mozambique.   Yet upon closer examination of the Malagasy&#8217;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 CÃ´tiers, 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 CÃ´tiers 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 <a id="t0-g" title="2005" href="http://www.cell.com/AJHG/retrieve/pii/S0002929707607368" target="_blank" rel="noopener">2005</a> 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&#8217;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 CÃ´tiers 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&#8217; analysis revealed a mixture of both African and Asian genetic ancestry, in both the Highlanders and the CÃ´tiers, which is perhaps contrary to the two groups&#8217; physical apperance.   So what does this mean?   That even the CÃ´tiers people, who often look more African in appearance, have an ancestry that traced back to Asia, specifically Borneo.   These results fit well with Hurles&#8217; study and with what linguists have been saying for years; that the Malagasy language &#8211; while clearly tracing back to Borneo &#8211; also has some African elements that are significant.
The results from these analyses then begged the next question &#8212; how and when did the earliest inhabitants of Madgascar arrive on the island?   Was it in two separate migrations &#8211; one from the east and one from the west &#8211; 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 &#8220;the encounter of people surfing the extreme edges of two of the broadest historical waves of expansion&#8221; 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.

New Study Reveals Complex Origins of the Malagasy

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Great apes really do giggle when tickled, new research says &#8211; just like you and me.
<h6>What&#8217;s So Funny</h6>
Researchers from the University of Hannover in Germany recorded the tickle-induced vocalizations from three human infants and 21 infant and juvenile orangutans, gorillas, chimpanzees and bonobos and analyzed this acoustic data to find similarities and differences among the five species.
Their results, published online today in the journal <a href="http://www.cell.com/current-biology/abstract/S0960-9822(09)01129-4" target="_blank" rel="noopener">Current Biology</a>, show that not only are the hoots, hollers and snorts of the great apes really laughter, but the evolutionary relationships between the sounds match up with the known evolutionary relationships between the species based on genetics.
&#8220;At a minimum, one can conclude that it is appropriate to consider &#8216;laughter&#8217; to be a cross-species phenomenon, and that it is therefore not anthropomorphic to use this term for tickling-induced vocalizations produced by the great apes,&#8221; the authors write.
<h6>Tickling</h6>
But the researchers&#8217; findings also indicate something more profound: rather than being a uniquely human invention, tickle-induced chuckles can be traced back 10 to 16 million years to our last common ancestor with the great apes. Analysis of the chortles of a lesser ape, the siamang, suggests that <a href="https://blog.23andme.com/articles/does-your-dna-make-you-lol">laughter</a> may be even older.
<img loading="lazy" decoding="async" class="alignleft size-medium wp-image-3729" title="slide1" src="https://blog-api.23andme.com/wp-content/uploads/2009/06/slide1-300x225.jpg" alt="" width="318" height="238" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/06/slide1-300x225.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2009/06/slide1.jpg 720w" sizes="auto, (max-width: 318px) 100vw, 318px" />The tree based on laughter matches the genetic tree. 
Despite the all the similarities the researchers found between humans and the great apes, the fact remains that human giggles are distinct — we mostly laugh while exhaling and our vocal chords vibrate to make the &#8220;ha ha ha&#8221; sounds, while ape snickers are more of the in-and-out panting variety.   The question for future research to answer is why particularly human features emerged and what functions they may have served as laughter became a large part of human social interaction.
Insanely cute video of giggling chimps here.

Evolutionary Link Between Human and Ape Laughter

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The 23andMe Personal Genome Service offers information about customers&#8217; maternal and paternal ancestry by examining their mitochondrial DNA (which we all inherit from our mothers) and the Y chromosome (passed by fathers to their sons).
Over our species&#8217; history, new genetic variations have arisen spontaneously in those pieces of DNA and passed down through the generations. So researchers know that every person alive today with a particular variation – say a T instead of a G at a specific spot on the mtDNA – is descended from a single common ancestor. By sampling people from around the world, scientists have assembled &#8220;family trees&#8221; that trace back to the dawn of the human species in eastern Africa more than 100,000 years ago. Those trees are the basis of the haplogroup assignments we give our customers. Each haplogroup represents a particular branch – and, therefore, a unique sequence of SNPs.
Now, using a feature we&#8217;ve developed called the Haplogroup Tree Mutation Mapper, you can see exactly which SNPs we use to generate the 23andMe mitochondrial and Y chromosome haplogroup trees. This isn&#8217;t the kind of information everyone would necessarily want, but several customers who are especially interested in genetic genealogy have requested it. It can be used to compare our haplogroup assignments to those obtained elsewhere, for example.

The Haplogroup Tree Mutation Mapper is the first arrival in 23andMe Labs, our new technology sandbox, where we will showcase experimental features not currently available in our Personal Genome Service.   These features may still be in development, require specialized knowledge, or be of interest only to a subset of our customers. Each lab will have its own community so customers can compare notes, ask questions, and share ideas.
Some labs will be requested by customers—in fact, we welcome your suggestions—and others will be dreamed up by our scientists.
Finally, labs will be somewhat less refined and fluid than those available within the Personal Genome Service. A feature could be discontinued at any time or elevated to full integration with our Personal Genome Service.
We&#8217;re really excited about this new outlet for our ingenuity, and we hope it will also engage some of you!

23andMe Labs Kicks Off With Haplogroup Tree Mutation Mapper

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It seems like new discoveries about the peopling of the Americas are a dime a <a id="c6ex" title="dozen" href="../2008/05/23/peopling-of-the-americas-times-two/" target="_blank" rel="noopener">dozen</a> these days. &nbsp; Without a doubt, the journey those first Americans took from the frozen wastelands of Asia down the Pacific coast into the Americas has been an active research subject for many decades. &nbsp; Archaeologists, linguists, and now geneticists have all analyzed the data in their respective fields, and while we have seen progress in figuring out the overall timing and migration routes across the <a id="ki2q" title="Bering Strait" href="https://en.wikipedia.org/wiki/Bering_Strait" target="_blank" rel="noopener">Bering Strait</a> during the height of the Ice Age, many questions remain unanswered. &nbsp; For example, there is still disagreement over whether there was a single wave of migrations into the New World around 18,000 years ago (a scenario generally favored by geneticists), or whether there were several separate migrations, each bringing across the Bering Strait its own distinct culture and languages (more popular among linguists).
Now, an international team of <a href="http://www.eurekalert.org/pub_releases/2009-01/cp-faa010509.php" target="_blank" rel="noopener">geneticists</a> has added to the debate by trying things a bit differently. &nbsp; While the majority of genetic studies have focused on the four most common mitochondrial DNA (mtDNA) types, or &#8216;haplogroups,&#8217; among Native Americans, these authors switched things up a bit. In study published online Thursday by Current Biology, they focused instead on two of the most rare and localized mtDNA haplogroups in the New World: D4h3 and X2a.

Mitochondrial DNA is passed down from mother to child exclusively. So by comparing the mtDNA of different populations, geneticists can estimate where and when their female lines diverged from one another.
Haplogroup D4h3 is usually found along the Pacific coast of South America, while X2a has been found only in north-central North America. &nbsp; The authors sampled a total of 55 individuals who fell into either one of these two groups. &nbsp; They sequenced the entire mitochondrial genome for each, thereby adding to the considerable lack of knowledge on these haplogroups; this was the first time that anyone completely sequenced representatives of either D4h3 or X2a.
The analyses of haplogroups D4h3 and X2a revealed two distinct genetic histories. That difference suggests they may have come from separate regions of Asia and expanded in the New World in very different directions, even though they both may have arrived around the same time.
Specifically, the authors argue that that, even though it appears that both D4h3 and X2a individuals arrived in the New World at about the same time period — between 14,000 and 17,000 years ago — they took very different routes to get there. The authors argue that D4h3 individuals crossed from Asia to the Americas via a coastal route; the same path the ancestors of most people bearing the major haplogroups are believed to have taken. Then, they continued down the Pacific coast, settling in various places along the way.
However, X2a individuals seemed to have embarked on a different journey. &nbsp; Avoiding the coast entirely, this group of people traveled through a small inland corridor between two major North American ice sheets, about 15,000 years ago. &nbsp; Then, they continued into the heart of North America, settling in what is now central Canada, where their descendants still reside today.
The results presented by the authors provide — perhaps for the first time — clear evidence that at least two separate routes were used by the earliest Paleo-Indians as they left East Asia and entered the Americas. &nbsp; But, and maybe even more importantly, it shows that the migrants who took these routes may have come from two different source populations. &nbsp; We can only hope that future research on these two haplogroups can reveal where in East Asia they originated, and maybe even what made them cross the frozen landscape in the first place &#8211; by land and by sea.

One if by Land, Two if by Sea:  New Genetics Study Indicates Multiple Paleo-Indian Migration Routes

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Less than eight nautical miles wide, the Strait of Gibraltar is an easily surmountable barrier between northwest Africa and Spain. Military invaders such as Hannibal of Carthage and the caliphs of the Islamic Empire have had no trouble traversing this sliver of sea in the process of invading Europe.
But in addition to those legendary military campaigns, countless unsung migrants have also crossed between the two continents via the so-called “Pillars of Hercules.” In fact, archaeologists have long speculated that people have been moving across the Strait — in both directions — for thousands of years.   Recently, genetics has also supported a prehistoric connection between the two continents.
Though most scientists who study North African genetics have focused their attention on connections to the Near East, recent studies have shown that the majority of North African genetic types, or haplogroups, suggest European ancestry.   The most recent evidence comes from a team of geneticists on both sides of the Mediterranean who collected samples from from more than 300 people living throughout Tunisia and analyzed their mitochondrial DNA (mtDNA). Passed directly by mothers to their offspring, mtDNA traces ancestry back thousands of years along an exclusively maternal line.

The researchers were especially interested in so-called ‘Andalusians,&#8217; who are descended from Spanish Muslims, or Moors, who were expelled from Spain in the 16th and 17th centuries after the <a id="sq8x" title="Reconquista" href="https://en.wikipedia.org/wiki/Reconquista">Reconquista</a> and <a id="db1q" title="Inquisition" href="https://en.wikipedia.org/wiki/Spanish_Inquisition">Inquisition</a>.   Because the ancestors of the Andalusians came to Spain from North Africa with the Muslim invasions of the 8th century, only to return to North Africa 900 years later, the researchers hoped their mtDNA might reveal a very interesting pattern of genetic ancestry.
After analyzing the mtDNA samples, the authors noticed some very interesting results indeed. Most of the samples belonged to the very diverse and distinctly European haplogroup H.   In some Tunisian communities nearly 45% of individuals belonged to that haplogroup.
Because haplogroup H is so diverse and widespread across Europe, the authors wanted to dig a bit deeper to find out if they could pinpoint the origin of the Tunisian haplogroup H lineages. They found that the most common sub-groups of haplogroup H in Tunisia were most commonly found in Western Europe, specifically Spain and Portugal. The sub-groups of H most often found in Eastern Europe and the Near East, on the other hand, were quite rare. Further analysis showed that people bearing these sub-H groups almost certainly entered North Africa via the Strait of Gibraltar.
The authors speculate that the migration occurred after the end of the Ice Age, perhaps 10,000 years ago. At that time, people began streaming out of the Iberian peninsula, where they had been confined for millennia by the mile-thick sheet of ice that covered northern and central Europe. These results show that — even before invading armies crossed the Strait of Gibraltar heading north, people carrying the H haplogroup passed through in the opposite direction.
But what about the Andalusians?   Does their mtDNA distinguish them from other Tunisians?   Can we see any genetic footprints of their recent expulsion from Iberia? Even after examining the mtDNA of Andalusians in fine detail, the authors were unable to distinguish them from other North African communities. It appears that the majority of the European influence on the genetics of North Africans occurred many thousands of years ago, when glaciers began to retreat and people expanded from Spain; both north into the heart of Europe, and south into Africa.

Prehistoric Connection between Iberia and North Africa

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My surname – Holden – has gone through many incarnations since it originated in England nearly 700 years ago.   Letters were added, then dropped.   Some branches of my family added an extra &#8220;u&#8221; in the middle, while others changed the pronunciation entirely.   Then, when my ancestors arrived in America over 200 years ago, the name went through a whole new set of changes.   It seems my surname has been in a constant state of change since its inception.
But the story of my surname is not unique.   Millions of Americans have similar stories about ancestors who, upon arriving in the New World, actively changed their names to sound more “American.” German immigrants named Blum became Bloom, KÃ¼sters became Custers, and KÃ¿fers became Coopers. Immigrants from Italy, Sweden, France, and countless other countries underwent similar transformations.   After just a few generations, the original spelling or pronunciation was lost.
Just as our surnames have changed over the centuries, little by little, so too has our DNA.   In fact, some regions of the human genome acquire mutations in such a way that researchers can trace the changes back through time — much like <a href="https://www.23andme.com/topics/ancestry/family-tree/">tracing a surname</a> back for generations in a family tree.   And one region in particular, the Y-chromosome, happens to be passed down from father to son, the same way surnames are inherited in Western culture. That provides a wealth of opportunities for scientists from a variety of disciplines to use the Y-chromosome to unlock history&#8217;s secrets, unravel family trees, and even solve crimes.

The Genetic Legacy of the Vikings
The histories of Scandinavia and the British Isles have been entwined since Vikings from Norway and Denmark landed on the eastern coast of England in the year 792.   Successful raiding parties eventually led to settlements along the eastern half of England.   Today there are remnants of Viking settlements in this region in the form of place names, unique vocabulary, and even surnames.   Last year, <a id="e6_-" title="British geneticists" href="http://mbe.oxfordjournals.org/cgi/content/abstract/25/2/301" target="_blank" rel="noopener noreferrer">British geneticists</a> took surname information from an area formerly settled by Vikings to see if men living there today who had Scandinavian surnames also had evidence of Scandinavian (aka Viking) genetic ancestry.   They analyzed the Y-chromosomes of several hundred men, and, not surprisingly, found that those with Scandinavian surnames did indeed have Scandinavian DNA, at least on the Y-chromosome.   Similar studies of Irish men have also found a modest connection between surnames and Y-chromosome types.
Surname DNA Projects
As we <a id="e_zg" title="reported" href="../2008/11/12/building-roots-from-the-ground-up-genealogy-20/" target="_blank" rel="noopener noreferrer">reported</a> several weeks ago, the field of genealogy has been invigorated by the increasing use of genetic testing to fill in the missing branches of a person’s family tree.   Genealogists are now comparing their Y-chromosomes to those of others with the same surname, to see if a shared surname is also an indication of the shared ancestry.   Within the past few years, <a id="xr16" title="surname projects" href="http://www.dnalist.net/" target="_blank" rel="noopener noreferrer">surname DNA projects</a> have sprung up all across the world &#8211; with hundreds of genetic genealogists digging deep into their genes as they piece together their detailed family trees.
Surnames and Forensics
By far one of the most interesting applications for surname and Y-chromosome comparison is in the field of forensic science.   In 2006, British geneticists found that — for some of the more rare surnames such as Maloy or Rivis, there was a strong connection between surname and Y-chromosome haplogroup.   The authors reasoned that, if DNA were to be recovered from a crime scene, forensic investigators might be able to narrow down the possible perpetrators to a specific subset of surnames.
However, there are several limitations to this idea — namely the fact that most men in the UK have rather common surnames, such as Smith, Green, and Adams.   Men with these surnames have a wide range of Y-chromosome DNA types, so it would nearly impossible for investigators to use the Y-chromosome to locate a suspect.   However, on principle this idea has merit, and further advances along these lines may someday allow investigators to exploit the DNA-surname connection.
One final note: 23andMe customers need not worry that their data will be used in this way – our research database does not include surnames and our <a href="https://www.23andme.com/about/privacy/" target="_self" rel="noopener noreferrer">terms of service</a> do not allow us to share data with law enforcement unless we are legally compelled to. And even if such a situation did arise, we have publicly <a href="http://cyberlaw.stanford.edu/node/5922" target="_blank" rel="noopener noreferrer">committed</a> to resisting legal requests for customer data.

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