On occasion, the Blog departs from its usual mission of bringing you the latest and greatest in human genetics news in order to report on particularly interesting discoveries in other species.
Many times these stories are about dogs and the reason is simple: dogs are awesome.
Well, there is more to it.
In addition to being faithful companions, dogs make great subjects for genetics research–the time between generations is much shorter in dogs than humans, they have multiple offspring per pregnancy and unlike in humans, it&#8217;s not unethical for scientists to decide which males and females breed together.
A luminary in the field of dog genetics is <a href="https://www.genome.gov/12513335" target="_blank" rel="noopener noreferrer">Elaine Ostrander</a>, chief of the Cancer Genetics Branch of the National Human Genome Research Institute.   Her lab uses dogs to study cancer susceptibility genes, but along the way they’ve made some fascinating discoveries about the incredible variation seen between the many breeds that make up the single species Canis lupus familiaris.
In 2007 Ostrander&#8217;s group showed that <a href="http://www.sciencedaily.com/releases/2007/04/070405144059.htm" target="_blank" rel="noopener noreferrer">small size in dogs</a>–think Chihuahuas and Pomeranians–can be traced to a single variant of the canine <a href="https://www.ncbi.nlm.nih.gov/pubmed/17412960?ordinalpos=16&amp;itool=EntrezSystem2.PEntrez.Pubmed.Pubmed_ResultsPanel.Pubmed_DefaultReportPanel.Pubmed_RVDocSum" target="_blank" rel="noopener noreferrer">IGF-1</a> gene.
Now, in a paper published online this week in <a href="http://www.sciencemag.org/cgi/content/abstract/1173275" target="_blank" rel="noopener noreferrer">Science</a> Express, they have shown that a single evolutionary event is behind the short, curved legs characteristic of all those adorable dachshunds, corgis and basset hounds.
<img loading="lazy" decoding="async" class="alignleft size-full wp-image-4080" title="dachsund" src="https://blog-api.23andme.com/wp-content/uploads/2009/07/dachsund.jpg" alt="dachsund" width="221" height="315" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/07/dachsund.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2009/07/dachsund-210x300.jpg 210w" sizes="auto, (max-width: 221px) 100vw, 221px" />
Ostrander&#8217;s group found that dogs having stubby little legs, technically termed chondrodysplasia, harbor an extra copy of a growth factor gene called FGF4.   But this is no ordinary gene duplication that happened as the result of a DNA replication error.
Instead, the researchers found that the extra copy of FGF4 is a retrogene, a piece of DNA copied from and then inserted back into the dog genome by a virus. Retrogenes are nothing new.   They&#8217;re known to be a major source of genetic change that takes place as different species split apart from each other.
But this new study is the first to show that a retrogene can cause long-lasting variation within a species. The various stumpy-legged dog breeds were developed in different places around the world, at different times and for various reasons.
So there&#8217;s no evidence that they share a recent common ancestor.   But the FGF4 retrogene appears to be identical in all of them, suggesting to the researchers that it arose only once, probably before early dogs split into modern breeds. These new findings don&#8217;t just represent an advance in the understanding of dog genetics, or even the fundamentals of DNA and evolution.   They also have implications for human health.   The type of growth disorder seen in the dogs with the retrogene is reminiscent of <a href="http://ghr.nlm.nih.gov/condition=hypochondroplasia" target="_blank" rel="noopener noreferrer">hypochondroplasia</a>, a type of dwarfism.   Scientists know that a mutation in one gene is responsible for most cases of this condition, but the cause of the rest remains a mystery.
According to Ostrander, her group&#8217;s results suggest that researchers interested in hypochondroplasia and other disorders of human growth and development should set their sights on FGF4. More Blog posts about dogs and genetics:
<ul>
<li><a href="https://blog.23andme.com/2008/11/07/gene-links-gout-in-humans-with-bladder-stones-in-dalmatian-dogs/" target="_blank" rel="noopener noreferrer">Gene Links Gout in Humans with Bladder Stones in Dalmatian Dogs</a></li>
<li><a href="https://blog.23andme.com/2008/08/07/learning-from-dog-eye-disorders/" target="_blank" rel="noopener noreferrer">Learning from Dog Eye Disorders</a></li>
</ul>
Picture Sources:
<ul>
<li><a href="https://en.wikipedia.org/wiki/File:MaddytheBHOUND.JPG" target="_blank" rel="noopener noreferrer">Basset hound</a></li>
<li><a href="https://en.wikipedia.org/wiki/File:Wire-haired_Dachshund_R_01.JPG" target="_blank" rel="noopener noreferrer">Dachshund</a></li>
</ul>

23andMe Blog

23andMe Blog Team

Single Gene Responsible For Stubby Legs In Dogs

<img loading="lazy" decoding="async" class="alignright size-full wp-image-4053" title="Biology experiment on well plate" src="https://blog-api.23andme.com/wp-content/uploads/2009/07/istock_000004124815xsmall.jpg" alt="Biology experiment on well plate" width="283" height="424" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/07/istock_000004124815xsmall.jpg 283w, https://blogcms.23andme.com/wp-content/uploads/2009/07/istock_000004124815xsmall-200x300.jpg 200w" sizes="auto, (max-width: 283px) 100vw, 283px" />
The exact causes of Crohn&#8217;s disease remain a mystery, but scientists do know that genetic factors play an important part. More than <a href="https://blog.23andme.com/articles/snpwatch-number-of-snps-associated-with-crohn%E2%80%99s-disease-triples/" target="_blank" rel="noopener">30 variations</a> have been associated with increased risk for the disease, but changes in one gene, NOD2, have been found to be especially critical. &nbsp; Three different variants in this gene have been associated with significantly increased risk for developing the disease. &nbsp; It&#8217;s estimated that 10-15% of people with Crohn&#8217;s disease have two copies of one of these variants.
Because changes in NOD2 are associated with so many cases of Crohn&#8217;s disease, medications made to interact with the protein the gene encodes would seem to be obvious candidates for drug development. &nbsp; But the NOD2 protein doesn&#8217;t have the type of function that can be modified by a drug.
A new avenue of drug research may have been opened, however, thanks to a study from Derek Abbott and colleagues at Case Western Reserve University. &nbsp; In a paper appearing in the August issue of <a href="https://dx.doi.org/10.1016/j.cub.2009.06.038" target="_blank" rel="noopener">Current Biology</a>, they show for the first time that a protein called ITCH can influence NOD2 biological pathways. &nbsp; This is important because, in the parlance of pharmaceutical development, ITCH is a &nbsp; &#8220;druggable&#8221; target.
NOD2 binds to bacteria that make their way into cells, setting off signals that activate the immune system. Research has shown that the Crohn&#8217;s disease-associated NOD2 variants decrease the signals that go through a particular protein called NFkB. &nbsp; Abbott&#8217;s lab found that ITCH also decreases NOD2-dependent NFkB signals. &nbsp; This is significant because studies have shown that increased NFkB signaling can help slow down the progression of Crohn&#8217;s disease.
&#8220;The thought is that if you could identify patients with NOD2 polymorphisms who also displayed early gastrointestinal trouble, you could block ITCH to increase NFkB signaling and not let the Crohn&#8217;s disease get to the acute stage,&#8221; Abbott said in an email.
Abbott and his fellow researchers are in the very early stages of looking for drugs that could be used to inhibit ITCH and possibly be useful in treating Crohn&#8217;s disease. &nbsp; But the road to drug discovery is a long one. &nbsp; ITCH interacts with many other proteins in cells and it&#8217;s not yet clear if blocking it would have unwanted effects on other important biological pathways. However, in the future this research could lead to a valuable drug against Crohn&#8217;s disease – at least for the 10 to 15% of patients who have variants that cause decreased NOD2 signaling.

Researchers Take A Step Toward Developing New Drugs For Crohn’s Disease

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There&#8217;s no shortage of books out there to help a woman know what to expect when she&#8217;s expecting, but when it comes to knowing how medications she might need during her pregnancy will affect her, there is very little guidance.
A woman&#8217;s body goes through profound physiological changes during pregnancy that have potential ramifications for the efficacy of a variety of drugs.   But despite a 1994 recommendation by the Institute of Medicine, most clinical trials still do not include pregnant women.   This means that for most drugs, doctors faced with a pregnant patient who needs a prescription have no choice but to guess the right thing to do.
&#8220;Any medicine taken to treat a woman&#8217;s illness during pregnancy — from hypertension to cancer, thromboembolism to asthma — is used without data adequate to guide dosing, make decisions about safety, or inform differential decisions about which medicine to prescribe.   The cost of this ignorance is profound,&#8221; Dr. Anne Lyerly and colleagues write in a recent article in the American Journal of Public Health.

The best strategy would be a large systematic study of women already taking medications during their pregnancies, so that there would be no extra risk for the unborn children.   According to Lyerly et al., just such an opportunity has presented itself in the form of the National Children&#8217;s Study (NCS).
The NCS aims to study the effects of the environment on 100,000 children from before birth to age 21.
Researchers hope to enroll 25% of the children before they are conceived, with 90% of the total being enrolled by the end of the first trimester. Lyerly et al. argue that this important study of children&#8217;s health also offers an unprecedented opportunity to collect information about the mothers too. But action must be taken soon to make sure that researchers don&#8217;t miss out on the chance to collect a wealth of information. Recruitment for the pilot phase of the study has already begun, and the final study protocol will be finalized in May 2010.


&#8220;Although the NCS will provide important and much-needed information about the effects of maternal medication use on the health of the fetus, absent is the other side of the coin: whether the medication is safe for the woman herself, whether it is effective in treating her underlying or emergent illness, and whether decisions to forgo medication or substitute older medications compromise her health,&#8221; the authors write.
Every additional piece of information collected will add to the already $3.2 billion projected cost of the NCS, but Lyerly et al. advocate for the inclusion of at least two additional research components:

<ul>
<li>Add questions to the surveys and medical chart evaluations already planned during the pregnancies of the women involved.</li>
<li>Take advantage of the maternal blood tests already planned to identify medications that are metabolized differently in pregnant women.   These drugs could then be investigated in more depth in follow-up studies.</li>
</ul>

&#8220;These two efforts together–at very little additional cost–would result in a rich data set that could lead to critical improvement in the care of pregnant women. Failure to include them would be hard to justify.&#8221;

Opportunity To Study Pregnant Women In Large National Study Must Not Be Missed, Experts Say

<img loading="lazy" decoding="async" class="alignright size-full wp-image-3956" title="800px-camel_cart_in_rann_of_kutch2" src="https://blog-api.23andme.com/wp-content/uploads/2009/07/800px-camel_cart_in_rann_of_kutch2.jpg" alt="800px-camel_cart_in_rann_of_kutch2" width="300" height="189" />
Most experts agree that the earliest examples of farming and animal domestication lie in the aptly named Fertile Crescent in present-day Iraq.
<h2>Earliest Farming Communities</h2>
But still, many questions have lingered over the years, especially about remnants of farming or animal domestication that have not survived to the present day.   What kind of tools did they use to farm the earliest crops? How did they transport these crops to neighboring communities? Now a new archaeological discovery in the mountains of Turkmenistan has finally given us more answers than questions, and has shed light on some of earliest farming communities in western Asia.
The finds center around discovering several model-sized carts at the archaeological site of Altyndepe, a Bronze Age settlement near Ashgabat in southern Turkmenistan. These tiny carts may have been used in ritual ceremonies or simply been young children&#8217;s toys.   However, the most interesting aspect of these carts is that they depict camels as the main beasts of burden. Archaeologists are always interested in artifacts from ancient civilizations that reveal clues about daily life, and these camel-pulled carts are a comparative jackpot.
<h2>Of Camels and Carts</h2>
An article about the carts recently appeared on the Discovery News website. They were documented by Lyubov Kircho of the Institute for the History of Material Culture at the Russian Academy of Sciences. They are described (in Russian) in the journal Archaeology, Ethnology and Anthropology of Eurasia. An English version will be published in the Proceedings of the 19th International Conference of the European Association of South Asian Archaeologists.
Archaeologists have discovered cattle-pulled carts from the region about 6,000 years ago. These carts were initially used for transporting necessities like grain but later carried other items like alabaster and the prized stone lapis lazuli from hundreds of miles away. Trade networks with neighboring communities began to spring up, and by 3,500 BC, one of the first dedicated &#8216;highways&#8217; for vehicles had been built between Altyndepe and nearby towns in present-day Iran and Afghanistan.
<h2>Influence of Climate</h2>
But by 3,000 BC, the climate was becoming more arid, and the people of Altyndepe could no longer trust their cattle-pulled carts to make the long journeys. Archaeologists already suspected that the communities must have switched to camels, which could handle the drier climate better. Now, these model carts show that their suspicions were correct; camel-pulled carts were the standard for this region and were such an integral part of daily life that miniature versions were created as children&#8217;s toys.
<h2>The Genetic History</h2>
The presence of these carts &#8211; combined with previous ideas on the sharing of ideas and culture throughout this part of Western Asia &#8211; also has implications for the genetic history of the region. It is well documented that about 10% of modern Europeans contain a genetic signature of the early agriculturalists who arrived from the Near East about 9,000 years ago, bringing their farming techniques and DNA.
Scientists now believe that while some of these Near Eastern farmers did travel west into the heart of Europe, others headed into the plateaus and foothills east of the Caspian Sea. Like their Western counterparts, these farmers brought their farming tools and techniques to the indigenous people of southern Turkmenistan. And like their Western counterparts, they probably got their genes. In fact, some genetic studies have examined the genetic makeup of modern-day residents of Turkmenistan and have found that many of these people also bear the genetic signatures of the early farmers of the Fertile Crescent.

Archaeologists Discover Early Example of Domesticated Camels

<img loading="lazy" decoding="async" class="alignright size-full wp-image-4024" title="nikolaus_kopernikus" src="https://blog-api.23andme.com/wp-content/uploads/2009/07/nikolaus_kopernikus.jpg" alt="nikolaus_kopernikus" width="300" height="349" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/07/nikolaus_kopernikus.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2009/07/nikolaus_kopernikus-258x300.jpg 258w" sizes="auto, (max-width: 300px) 100vw, 300px" />
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.
<h6>A Book</h6>
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&#8217;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&#8217;t visit his grave; until recently, no one could find his body.

<h6>A Body</h6>
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 <a id="lol5" title="Proceedings of the National Academy of Sciences: USA" href="https://www.pnas.org/content/early/2009/07/06/0901848106.abstract" target="_blank" rel="noopener">Proceedings of the National Academy of Sciences: USA</a>.
<h6>DNA Analysis</h6>
Prior to the DNA analysis, anthropologists had performed digital facial reconstruction on many of the crypt&#8217;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&#8217;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.
<h6>Some Hair</h6>
Yet even after successfully extracting mtDNA from the skeleton&#8217;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 &#8211; with not even a single letter of DNA code out of place &#8211; 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&#8217; 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.

DNA Analysis Confirms Remains of Nicolaus Copernicus

<img loading="lazy" decoding="async" src="https://blog-api.23andme.com/wp-content/uploads/2009/07/geneticresearch7.jpg" alt="geneticresearch7" title="geneticresearch7" class="alignright size-full wp-image-4013" width="350" height="268" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/07/geneticresearch7.jpg 350w, https://blogcms.23andme.com/wp-content/uploads/2009/07/geneticresearch7-300x230.jpg 300w" sizes="auto, (max-width: 350px) 100vw, 350px" />
There&#8217;s a high likelihood that a disease of some sort affects you or one of your relatives – every family seems to have ripples in its gene pool that define and shape its health dynamics.
Your family might have a propensity for rheumatoid arthritis or a particular type of cancer. Whatever it is, there can be an instant family bond created by that disease – along with a sense of fate.
That feeling moves some families to action. The Heywood brothers started <a href="http://www.patientslikeme.com" target="_blank" rel="noopener noreferrer">PatientsLikeMe</a> when one of them, Stephen, was diagnosed with Lou Gehrig&#8217;s disease in 1998. Nancy Brinker created a huge force in breast cancer research through the <a href="http://www.komen.org/" target="_blank" rel="noopener noreferrer">Susan G. Komen Foundation</a>, named for her sister who died of that disease. Michael J. Fox, a father of four, started his remarkable <a href="http://www.michaeljfox.org/" target="_blank" rel="noopener noreferrer">foundation</a> after he was diagnosed with Parkinson&#8217;s disease at the age of 30.
But not everyone can garner the resources to create their own company or foundation; it&#8217;s hard to know where to turn in trying to make a difference. This summer, 23andMe is launching the <a href="https://www.23andme.com/researchrevolution/" target="_self" rel="noopener noreferrer">Research Revolution</a> to empower more people to jumpstart genetic research into the diseases that affect them and the people they love.

This new research model makes it possible for large groups of people to assemble themselves into large-scale genetic studies without having to raise millions of dollars in funding, and then wait years for things to get rolling. Participants also get access to their own genetic information through the 23andMe Personal Genome Service Research Edition, which offers a snapshot of what their data says about more than 100 diseases and traits. We believe that if you volunteer for research, you should be able to see what you&#8217;ve contributed to the effort.
The Research Revolution is going to start with the 10 diseases listed at the bottom of this post. There are several ways you can participate:
* Visit the <a href="https://www.23andme.com/researchrevolution/" target="_self" rel="noopener noreferrer">Research Revolution page</a> and vote for the disease you would most like 23andMe to study. 
* If you&#8217;re already a 23andMe customer, log into your account and complete any of the 23andWe <a href="https://www.23andme.com/you/23andwe/surveys/" target="_self" rel="noopener noreferrer">surveys</a> you haven&#8217;t taken yet. 
* Spread the word – especially to people who are patients or survivors of the 10 diseases we&#8217;re featuring.
There&#8217;s strength in numbers. The more people who enroll in the Research Revolution, the more likely it is to make new discoveries about the causes and about the treatments of disease.
Long live the revolution!
The 10 Research Revolution diseases are:
ALS 
Celiac Disease 
Epilepsy 
Lymphoma and Leukemia 
Migraines 
Multiple Sclerosis 
Psoriasis 
Rheumatoid Arthritis 
Severe Food Allergies 
Testicular Cancer

Introducing a Do-It-Yourself Revolution in Disease Research

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Schizophrenia, a devastating mental illness that affects about one out of every 100 people, is known to have a large genetic component. But scientists have had little luck in finding genes that are responsible for large numbers of cases.   This in turn has hindered the search for new treatments that could provide relief to the tens of millions of schizophrenics worldwide.
But now new research has identified several common DNA variants that can influence the risk of developing schizophrenia. The key to this new success was data sharing &#8211; three large consortia combined their data to enable analysis of almost 13,000 people with schizophrenia and more than 34,000 controls.
All three research groups (<a href="https://dx.doi.org/10.1038/nature08186" target="_blank" rel="noopener">SGENE</a>, <a href="https://dx.doi.org/10.1038/nature08185" target="_blank" rel="noopener">International Schizophrenia Consortium</a> and the <a href="https://dx.doi.org/10.1038/nature08192" target="_blank" rel="noopener">Molecular Genetics of Schizophrenia</a> group) found that variants in a region of DNA that harbors multiple immune-related genes are strongly associated with schizophrenia.   Their results, published this week in Nature, fit with previous data suggesting that there is an autoimmune component to the disease.   These ideas stemmed from data showing that schizophrenics are more likely to be born in the winter or spring, the height of flu season.
As an example of one of these immune region variants, the SGENE analysis found that each C at increased the odds of schizophrenia by 1.19 times compared to someone with two Ts at this SNP.
The SGENE researchers associated two other variants with schizophrenia – in the NRGN gene on chromosome 11 and in the TCF4 gene on chromosome 18 –  that are known to be involved in brain development and cognition. These findings may open up avenues into research for new treatments able to address problems with decision-making and memory in ways that current schizophrenia medications do not.
The NRGN is expressed exclusively in the brain where it plays an important role in chemical pathways related to memory. Each copy of the more common T version of increased the odds of schizophrenia by 1.15 times compared to two copies of the C version.
The protein encoded by the TCF4 gene is essential for normal brain development.   Mutations in this gene have been associated with several disorders characterized by mental retardation.   Each copy of the C version of increased the odds of schizophrenia by 1.23 times.
Last year, several studies suggesting that <a href="https://blog.23andme.com/2008/03/28/schizophrenia-genetics-in-science-snps-are-only-one-piece-of-the-puzzle/" target="_blank" rel="noopener">rare insertions and deletions</a> in the DNA were common in schizophrenia cast doubt on whether genomewide association studies would ever identify common genetic variants associated with the disease. But the results of the International Schizophrenia Consortium show that there are in fact thousands of common variants that show at least some association with schizophrenia.   The authors say that although the effect of each individual variant is small, together they account for at least a third of the disease risk.
&#8220;Our results do not exclude important contributions of rare variants for schizophrenia,&#8221; the authors write. But their results do show that sequencing and studies of insertions and deletions cannot be the only methods used to study the genetics of schizophrenia. Further genomewide association studies of common variations will also need to be undertaken.
The International Schizophrenia Consortium analysis also found that many of the variations associated with schizophrenia are also associated with bipolar disorder, a finding at odds with the traditional view of psychiatrists that the two are distinct diseases.
&#8220;These new results recommend a fresh look at our diagnostic categories.   If some of the same genetic risks underlie schizophrenia and bipolar disorder, perhaps these disorders originate from some common vulnerability in brain development,&#8221; said Dr. Thomas Insel, director of the National Institute of Mental Health, in a statement.
&#8220;Of course the big question then is how some people develop schizophrenia and others develop bipolar.&#8221;

Researchers Show Importance Of Common DNA Variants In Schizophrenia

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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.
<h6>Free People</h6>
The Tuareg call themselves the Imazghan, meaning &#8220;free people.&#8221; 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.
<h6>Uncovering a mystery with DNA</h6>
Though known to scholars since Herodotus&#8217; depiction thousands of years ago, the Tuaregs remain shrouded in mystery. Their extreme isolation in one of the earth&#8217;s harshest environments has made them difficult for cultural anthropologists to study.   There have been only a handful of studies published on the Tuaregs&#8217; 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.
<h6>A Surprising Haplogroup</h6>
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&#8217; 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.
<h6>Genetic Isolation</h6>
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.
<h6>The Tuaregs Origins</h6>
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.

People of the Veil: New Study Reveals Clues to Origins of the Nomadic Tuaregs

<img loading="lazy" decoding="async" class="alignright size-full wp-image-3873" title="408px-pompeii_garden_of_the_fugitives_02" src="https://blog-api.23andme.com/wp-content/uploads/2009/06/408px-pompeii_garden_of_the_fugitives_02.jpg" alt="408px-pompeii_garden_of_the_fugitives_02" width="300" height="440" srcset="https://blogcms.23andme.com/wp-content/uploads/2009/06/408px-pompeii_garden_of_the_fugitives_02.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2009/06/408px-pompeii_garden_of_the_fugitives_02-205x300.jpg 205w" sizes="auto, (max-width: 300px) 100vw, 300px" />
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.

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