DNA has been described as both a recipe for life and a record of it, and computational biologist John Novembre – who recently received a MacArthur Foundation “genius grant” for his work – is showing just how powerful melding those two elements together can be for scientists.

<div id="attachment_23026" style="width: 310px" class="wp-caption alignright"><img loading="lazy" decoding="async" aria-describedby="caption-attachment-23026" class="size-medium wp-image-23026" src="https://blog-api.23andme.com/wp-content/uploads/2015/10/Novembre_2015_hi-res-download_2-300x243.jpg" alt="John November Photo Courtesy: John D. &#038; Catherine T. MacArthur Foundation" width="300" height="243" srcset="https://blogcms.23andme.com/wp-content/uploads/2015/10/Novembre_2015_hi-res-download_2-300x243.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2015/10/Novembre_2015_hi-res-download_2-768x623.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2015/10/Novembre_2015_hi-res-download_2-880x714.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2015/10/Novembre_2015_hi-res-download_2.jpg 1000w" sizes="auto, (max-width: 300px) 100vw, 300px" />Photo Courtesy of the John D. &amp; Catherine T. MacArthur Foundation</div>
Novembre, who we first wrote about seven years ago, was recognized for his innovative research that used aggregated genetic information to create “genetic maps” of Europe, and he also lead a team that studied the recombination rates in admixed individuals, particularly African Americans.
Using what we know about recombination rates, he has been able to pinpoint when rare genetic variants emerged in human populations.
23andMe population geneticist Kasia Byrc, who was a co-author on Novembre’s “Genes Mirror Geography in Europe” paper said she liked that there is often a strong geographic component to his work.


“A lot of his work is focused on understanding the geography of genetic variation, and in turn, learning about what a population&#8217;s history was based on looking at the present-day genetic patterns. He&#8217;s also a brilliant computational biologist.”


While at UCLA Novembre developed ADMIXTURE, an ancestry-estimation algorithm that powers some genetic ancestry testing company’s results. The algorithm took what was previously an innovative, but computationally slow method – called STRUCTURE – and created a much faster algorithm to make these estimations possible with very large and rapidly-growing datasets., Kasia said.


His work is improving scientists’ ability to estimate recombination rates within admixed populations. This is helping researchers understand how genetic material gets shuffled up before it gets passed on to the next generation.
But beyond insights about ancestry, Novembre’s detailed study looking at the introduction of rare and damaging genetic variants into the human genome will add to our understanding of the genetics of certain disease and how it differs among different populations.
<iframe loading="lazy" width="560" height="315" src="https://www.youtube.com/embed/czVNYdtAaB8" frameborder="0" allowfullscreen="allowfullscreen"></iframe>

23andMe Blog

23andMe Blog Team

Mapping It Out

In a new study published in the <img loading="lazy" decoding="async" class="alignright wp-image-21956 size-medium" src="http://35.88.189.111/wp-content/uploads/2014/11/Kasia1-197x300.jpg" alt="" width="197" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2014/11/Kasia1-197x300.jpg 197w, https://blogcms.23andme.com/wp-content/uploads/2014/11/Kasia1.jpg 369w" sizes="auto, (max-width: 197px) 100vw, 197px" />
<h6>Regional Ancestry Differences</h6>
The study offers a detailed look at how the ancestry make-up of self-identified African Americans, Latinos and European Americans differs by region and these differences reflect some of the distinctive socio-political history in different parts of the United States.
“Our study not only reveals the historical underpinnings of regional differences in genetic ancestry, but also sheds light on inconsistencies between genetic patterns and commonly accepted notions of race and ethnicity,” Kasia said.
<h6>DNA USA</h6>
Although the study doesn’t pretend to be a comprehensive portrait of the genetic makeup of the United States, it’s unprecedented in its scope and it does show how the history of the Americas as a crossroad for disparate cultures is written in our DNA.
Using aggregated and anonymous data from 160,000 23andMe customers who consented to research, Kasia looked at how the ancestral make-up for whites, blacks and Latinos differed in each state. Some of what she found is well known, but some of the data illuminates a United States with a much more complicated multicultural history than many of us understand.

		<style type="text/css">
			#gallery-1 {
				margin: auto;
			}
			#gallery-1 .gallery-item {
				float: left;
				margin-top: 10px;
				text-align: center;
				width: 50%;
			}
			#gallery-1 img {
				border: 2px solid #cfcfcf;
			}
			#gallery-1 .gallery-caption {
				margin-left: 0;
			}
			/* see gallery_shortcode() in wp-includes/media.php */
		</style>
		<div id='gallery-1' class='gallery galleryid-21992 gallery-columns-2 gallery-size-thumbnail'><dl class='gallery-item'>
			<dt class='gallery-icon landscape'>
				<img loading="lazy" decoding="async" width="150" height="150" src="https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-150x150.jpg" class="attachment-thumbnail size-thumbnail" alt="" srcset="https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-150x150.jpg 150w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-300x300.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-768x768.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-1024x1024.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-880x880.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-1180x1180.jpg 1180w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-271x271.jpg 271w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-372x372.jpg 372w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-574x574.jpg 574w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-Among-African-Americans-980x980.jpg 980w" sizes="auto, (max-width: 150px) 100vw, 150px" />
			</dt></dl><dl class='gallery-item'>
			<dt class='gallery-icon landscape'>
				<img loading="lazy" decoding="async" width="150" height="150" src="https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-150x150.jpg" class="attachment-thumbnail size-thumbnail" alt="" srcset="https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-150x150.jpg 150w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-300x300.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-768x768.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-1024x1024.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-880x880.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-1180x1180.jpg 1180w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-271x271.jpg 271w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-372x372.jpg 372w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-574x574.jpg 574w, https://blogcms.23andme.com/wp-content/uploads/2014/12/African-Ancestry-in-White-Americans-980x980.jpg 980w" sizes="auto, (max-width: 150px) 100vw, 150px" />
			</dt></dl> 
		</div>

<h6>Hidden African Ancestry</h6>
Among her findings were that about 3.5 percent of self-identified European Americans have at least 1 percent or more African Ancestry. It’s likely that many of these Americans, who describe themselves as white, may be unaware of their African ancestry, which in many cases goes back between five to ten generations. There are also differences regionally – with the highest levels in the South – so that in South Carolina, at least 13 percent of self-identified whites have 1 percent or more African ancestry, while in Louisiana the number is a little more than 12 percent.
In Georgia and Alabama the number is about 9 percent. The differences perhaps point to different social and cultural histories within the South.
Among black Americans, those with the highest percentage of African ancestry also live in southern states, especially South Carolina and Georgia. The percentage of the population who are African Americans are also highest in those states, but there are also differences among states with similar percentages of African Americans.
<h6>Native American Ancestry</h6>
That may also be due to the different histories of those states. Kasia’s study also found that one in every 20 African Americans have Native American ancestry, while in Oklahoma 14 percent of African Americans carry at least two percent Native American ancestry.
Among self-reported Latinos in the US, those from states in the southwest, especially from states bordering Mexico, have the highest levels of Native American ancestry.
But among Latinos too there were wide regional differences that also likely reflect the history of migration and intermixing. For example, some Latinos have no discernible Native American ancestry, while others have as much as 50 percent of their ancestry being Native American. Latinos in states in the Southwest, bordering Mexico – New Mexico, Texas, California and Arizona – have the greatest percentage of Native American ancestry. Latinos in states with the largest proportion of African Americans in their population – South Carolina, Louisiana and Alabama – have the highest percentage of African Ancestry.
All three groups — African Americans, European Americans and Latinos — showed asymmetrical male and female ancestry contributions, with more European male and more Native American and African female ancestors. This asymmetry is likely a legacy of slavery, unbalanced sex ratios in frontier settings, as well other social factors.

Ancestry Across the United States

Stephanie Griffith-Jackson always believed her ancestry was diverse, but she never suspected her DNA would lead her to France.<img loading="lazy" decoding="async" class="alignright size-full wp-image-21038" src="https://blog-api.23andme.com/wp-content/uploads/2014/05/Stephanie-Jackson.jpg" alt="Stephanie Jackson" width="260" height="196" />
Interested in her African American ancestry and her family health history, Stephanie tested with 23andMe to learn more. The results surprised her.
“I’ve always been a mutt, and proud of it but this takes it to a whole new level,” Stephanie said.
<h6>African and European Ancestry</h6>
She learned that along with her African ancestry she had a much larger percentage of European ancestry than she expected. With a little more research into her genealogy, Stephanie discovered that her great-grandfather was Welsh.   He married her great-grandmother, who was African American, in the early 1900’s.
“It’s tough to find information on that side of the family, because after the wedding, my great-grandfather’s family disowned him for marrying outside his race,” she said. “It makes me want to cry to think about that story.  He risked everything for love.”
<h6>Connecting to Other Cultures</h6>
The more Stephanie learned about the “various and wonderful cultures” she came from, the more she wanted to connect with them.
Using 23andMe&#8217;s DNA Relatives tool, Stephanie reached out to several distant cousins, including one living in France. This cousin turned out to be an ex-pat Californian named Terry. Terry and Stephanie connected through 23andMe, and then started communicating online.  They found that they have a remarkable amount of similarities.
<h6>Cousins</h6>
When the pair had a chance to get together in California, where Stephanie now lives. The two distant cousins got along like childhood best friends.
“When we first saw each other, we screamed, hugged and cried,” said Stephanie. “We stayed up until four in the morning.  We were connecting, so we didn’t want to stop talking.  It was like we had known each other forever.  It was strange. I felt like I’d already met her like I already knew her.”
The pair also found that they shared a strong interest in genealogy.   Stephanie has been exploring her African roots and recently took a trip to Africa.  She even started a website for people who wanted to explore their genealogies.
&#8220;I will never be the same after getting my DNA tested,” Stephanie says.  “I’ll never think of myself in the same way. We are all connected. We are all family.”
Stephanie continues to research her genealogy, including her Native American and Portuguese roots on her mother’s side.  She and Terry talk every day.
“I&#8217;m so happy to have found 23andMe,” said Stephanie.  “I have discovered that color doesn’t separate us.  I truly believe that if everyone had the opportunity to have their DNA tested, it would do a lot to lessen prejudice in the world and bring people closer together.”
23andMe provides genetic testing services for informational purposes; your results may or may not help you to search for or identify relatives or family members.
&nbsp;

Connecting Cousins

<img loading="lazy" decoding="async" class="aligncenter wp-image-19265 size-full" src="http://35.88.189.111/wp-content/uploads/2013/09/Mike-Lattimore-02-scaled.jpg" alt="" width="2560" height="1707" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-02-scaled.jpg 2560w, https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-02-300x200.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-02-768x512.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-02-1024x683.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-02-880x587.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-02-1180x787.jpg 1180w" sizes="auto, (max-width: 2560px) 100vw, 2560px" />
Mike Lattimore felt a mix of anxiety and dread about visiting Africa, so fraught it was with the scars of slavery.
But standing on the shores of what is known as the “Slave River” near the Cape Coast of Ghana, where men and women were once bathed before they were sold into slavery, Mike felt a sense of peace instead of horror.
“We had a ritual,” he said.
In his journey to explore his ancestry, Mike, a 57-year-old who lectures on cyber security, turned to 23andMe’s genetic testing to guide the way.
Using 23andMe’s ancestry tools, Mike learned more about his mixed heritage rooted in both Africa and Russia. The information has filled in big gaps in his family history and helped Mike add more pages to what he likes to call “The One Story” tracing back the lives of his ancestors.
“23and me pointed me in the right direction in terms of knowing which records to sift through, which direction to go,” he said.
Standing there with other African Americans, Mike felt he was answering the prayers of his ancestors, a plea that their children and children’s children would be better off than they were. He saw evidence of that answered prayer in his own life – his family, his job and the things he’d achieved–and in the fact that he was able to return to tell the story of what had happened there.
<div id="attachment_19260" style="width: 310px" class="wp-caption alignright"><img loading="lazy" decoding="async" aria-describedby="caption-attachment-19260" class="size-medium wp-image-19260" src="https://blog-api.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-08-300x200.jpg" alt="A photo of Mike's mother in front of some art from Africa." width="300" height="200" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-08-300x200.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-08-768x512.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-08-1024x683.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-08-880x587.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2013/09/Mike-Lattimore-08-1180x787.jpg 1180w" sizes="auto, (max-width: 300px) 100vw, 300px" />A photo of Mike&#8217;s mother in front of some art from Africa.</div>
“It was a powerful and healing experience,” he said. “Good indeed did come out of that story. Light came out of the darkness of what happened there.”
His results from 23andMe didn’t just point him to Africa, but to his European ancestry and it reminded him of the interconnections of all people.
With his results he knew that his ancestors were likely from West Africa, but here was more than the science pointing him in that direction. When he walked among the Fante people he was overcome with a strong sense of kinship. They had the same orientation toward the water and fishing his own family had.
“I was struck by the people, there was something about the music and the energy it just felt right,” he said.
He knows that his E1a haplogroup points to ancestry in West Africa, but beyond the test results, Mike felt something deeper. He felt he was one of them.
The journey back to Africa capped a more than ten-year quest to discovery his ancestry, a hunt that included finding birth and death certificates in a rural town in Kentucky, contacts in Newfoundland and a convent in Baltimore.
The results from 23andMe also linked him to his mixed ancestry, one that is rooted in Africa, but includes both Jewish and, surprisingly to him, Scandinavian ancestry.
“My ancestors came from disparate places on the planet but all have lived the story of the struggle to seek a better life,” Mike said. “When I think about it, it gives me goose bumps because I am the sum total of all that they were, and now, I am the keeper of the memory.”
Some of that history Mike had heard from his own father. He heard about his great grandfather, Rush Green, who’d been owned by a man named Miller. Upon gaining his freedom his grandfather took the name “Green,” because he liked it.
“He told Papa, ‘a man has got the right to name his-self.’”
In his chronicling of his “One Story,” Mike has found his great grandfather’s grave in Paducah Kentucky, an “Aunt Minnie,” born in Russia whose native language was Yiddish, and records of his mother’s life being raised by the Oblate Sisters of Providence, an order of black Catholic nuns in Baltimore. He found records of his grandmother, Mary Brace, a white Canadian woman who had to give up his mother for adoption.
Through 23andMe he’s found relatives he didn’t know he had and he continues to fill in more pages of his family history.
“I strongly feel that we should invest in finding our ancestry because it really helps us as human beings not only to have a legacy that we can pass down but also to help with the healing,” Mike said. “Our country has experienced a great rift in that we have never fully investigated what happened. You’ve got to know where you’ve been so that you know where you’re going.”
23andMe provides genetic testing services for informational purposes; your results may or may not help you to search for or identify relatives or family members.

The Keeper Of Memory

<img loading="lazy" decoding="async" class="aligncenter wp-image-18480 size-full" src="http://35.88.189.111/wp-content/uploads/2013/06/AA-Menarche--scaled.jpg" alt="" width="2560" height="1978" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--scaled.jpg 2560w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--300x232.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--768x593.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--1024x791.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--880x680.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--1180x912.jpg 1180w" sizes="auto, (max-width: 2560px) 100vw, 2560px" />By Anne Pinckard
The high rates of <a href="https://blog.23andme.com/ancestry/african-ancestry-and-risk-for-type-2-diabetes/">type 2 diabetes</a> in some minority communities as well as the rates for <a href="https://blog.23andme.com/23andme-research/ethnicity-matters-in-research-a-case-study-in-prostate-cancer/">prostate cancer</a> among African American men are a good illustration of how a person’s risk for a disease can depend on ancestry.
The problem is scientists haven’t done enough research in minority communities to be able to learn just how much of a role ancestry plays in the development of those and other diseases. While some of the differences in risk may be due to environment and lifestyle, it’s a good bet that genetics also plays a role.
A recent study highlights why it’s so important to conduct ancestry-specific research, and why research findings are difficult to apply across different ethnicities. In this case, scientists were investigating the genetic influences of breast cancer in African-American women.
Most of the genetic factors linked to breast cancer were discovered among women of European and Asian ancestry. But African American women not only have higher rates of breast cancer, but they are 40 percent more likely to die from the disease than women of European ancestry. African-American women also tend to be diagnosed at a younger age and are more likely to experience the more aggressive types of the disease. While there may be many factors involved in these differences, including access to early screening and quality care, understanding the role genetics may play in these differences is also important.
The study, titled <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0058350">“Evaluating Genome-Wide Association Study-Identified Breast Cancer Risk Variants in African-American Women” </a>  and published by the peer-reviewed journal <a href="http://www.plosone.org/">PLOS One</a>, claims to be the first to examine all the known breast cancer genetic markers in African-American women. The international team of scientists looked at 67 genetic variants associated with breast cancer in women of Asian and European ancestry. This is the first study to investigate how relevant these variants are in African-American women, say the researchers. To find out, they tested the DNA of about 1200 African-American women diagnosed with breast cancer and 2,000 African-American women who served as a control group.
What researchers found was that only about 10 percent of the genetic markers associated with breast cancer in women of Asian and European ancestry were found to have significant associations with breast cancer in African American women. In that group of genetic markers associated with breast cancer among African American women, researchers found one that is linked to one of the more aggressive types of breast cancer – known as estrogen receptor (ER)-negative breast cancer. This type of breast cancer is also much more prevalent among African American women.
The findings also mean, of course, that 90 percent of the markers associated with breast cancer in European-and Asian-American women aren’t necessarily linked to the disease in African-American women. This conclusion is consistent with results from previous studies.
But the new study underscores the complexity of applying previous research to a specific population, and the need for more large-scale studies on African-American women.

More Diversity Needed in Genetic Research

<img loading="lazy" decoding="async" class="alignright wp-image-18480 size-medium" src="http://35.88.189.111/wp-content/uploads/2013/06/AA-Menarche--300x232.jpg" alt="" width="300" height="232" srcset="https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--300x232.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--768x593.jpg 768w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--1024x791.jpg 1024w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--880x680.jpg 880w, https://blogcms.23andme.com/wp-content/uploads/2013/06/AA-Menarche--1180x912.jpg 1180w" sizes="auto, (max-width: 300px) 100vw, 300px" />Several studies have shown that certain girls, particularly <a href="https://www.ncbi.nlm.nih.gov/pubmed/16356426">African-American girls</a>, experience puberty earlier than others, but there’s an ongoing debate about what that might mean.
There are several reasons why some girls begin puberty earlier than others. Heavier girls tend to enter puberty earlier than thinner girls, while there are also disorders that can trigger “<a href="https://en.wikipedia.org/wiki/Precocious_puberty">precocious puberty</a>”– or puberty before age eight. <a href="https://www.ncbi.nlm.nih.gov/pubmed/23348069">Environmental factors</a>, such as nutrition and certain chemicals, also can play a role.  Understanding the genetic components that influence when a girl begins menstruating – also known as her age at menarche (“men-AR-kee”) – could also help scientists better understand the genetic factors behind diseases associated with early puberty, including <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2842205/">type 2 diabetes</a> and <a href="https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3488186/">breast cancer</a>.
But to date, the scientific community has overlooked a core population that is perhaps most at risk. Today, African-American women tend to begin menstruating four to six months earlier than girls of European descent. Later in life, African-American women also have a higher risk for obesity, hypertension, and metabolic disorders, including diabetes. These two trends could be related, and genetic factors could be a common denominator.
A <a href="http://hmg.oxfordjournals.org/content/early/2013/05/01/hmg.ddt181.full.pdf">new study</a> of African-American women looked explicitly at genetic variations contributing to age at menarche. The research, done by a multi-institutional team of scientists, crunched data from 15 studies, including information from over 18,000 women.
Their findings indicate differences in DNA that could help scientists better understand the genetics of menarche timing in all women and the development of diseases associated with early menarche.
We’ve written before about the importance of considering ancestry when analyzing trends in disease. Certain diseases are more prevalent in specific populations. For instance, African-American men are more likely to develop and die from<a href="https://blog.23andme.com/23andme-research/ethnicity-matters-in-research-a-case-study-in-prostate-cancer/"> prostate cancer</a> than people of European descent.  African Americans also tend to be at higher risk for type 2 diabetes, while people of European descent are at higher risk of the heart rhythm disorder atrial fibrillation.
Given the difference in risk, it seems imperative that researchers investigate a diversity of populations to better understand the genetic factors behind these diseases. Yet research on populations with non-European ancestry continues to lag.
In this case study, the researchers performed a meta-analysis of existing research to search for DNA variants associated with earlier menarche in African-American women. Then they compared their results to data from women of European descent. The variants, called SNPs (or single-nucleotide polymorphisms), can account for some of the differences in biological traits, in this case, early menarche, between two individuals. These variants, in turn, can help scientists identify the genes and biological mechanisms controlling menarche timing.
Out of 42 SNPs associated with age at menarche in European women, 25 were also associated with the trait in African-American women, bolstering the evidence that these genes&#8217; genetic variants are tied to menarche timing. However, they also found variants in eight genome regions that were more strongly associated with age at menarche in African-American women than in European-American women. Many of these regions contain genes influencing obesity, underscoring the link between body fat and early menarche. Other areas include genes associated with breast and other cancers.
Although this is the largest and most comprehensive study, the total number of data samples of African-American women available to the researchers was still fewer than are now available for European-American women. And yet, the study demonstrates an important fact: by studying diverse ethnicities, scientists can refine their understanding of the role genes play in all populations.

Genetics, Puberty and African American Girls

<img loading="lazy" decoding="async" class="alignright size-medium wp-image-6445" title="elderly_1" src="https://blog-api.23andme.com/wp-content/uploads/2010/04/elderly_1-300x199.jpg" alt="" width="300" height="199" srcset="https://blogcms.23andme.com/wp-content/uploads/2010/04/elderly_1-300x199.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2010/04/elderly_1.jpg 425w" sizes="auto, (max-width: 300px) 100vw, 300px" />
A study published in March in the journal <a href="http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0032840">PLoS ONE</a> suggests that having more African ancestry is associated with higher risk for type 2 diabetes.
Type 2 diabetes is one of the most common chronic diseases in the United States, affecting about 26 million people and more than 25% of the population over the age of 65. While most people realize that lifestyle factors like an unhealthy diet and lack of exercise increase the risk of developing the disease, many may not realize that ancestry plays a role, too. In fact, type 2 diabetes strikes non-white ethnic groups at higher rates, with African Americans experiencing the highest rates of all. 
 
Higher rates of obesity and heart disease, and lower socioeconomic status in the African American population certainly contribute to this trend, but, as <a href="http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0032840">this study</a> found, those factors aren’t the whole story. Led by Ching-Yu Cheng and Linda Kao from Johns Hopkins University, the research team analyzed DNA from more than 7,000 African Americans and found that those with the most (&gt; 87.5%) African ancestry had about 33% higher odds of type 2 diabetes compared to those with the least (&lt; 80.5%) African ancestry after accounting for body mass index (BMI) and socioeconomic status.
<div style="padding: 10px; margin-left: 15px; float: right; border: 1px solid #ccc; width: 280px;">
<img loading="lazy" decoding="async" class="alignleft size-full wp-image-12163" title="small_23andMe_logo" src="https://blog-api.23andme.com/wp-content/uploads/2012/04/JRBgdIBXKIeVIdETJrxYIw_ttam_logo.jpg" alt="" width="24" height="40" />
See your <a href="https://www.23andme.com/you/ancestry">ancestry breakdown</a> in your 23andMe account.
Not yet a customer? <a href="https://www.23andme.com/store">Visit our store</a>!
</div>
A person’s ancestry can be traced back to various regions of the world (e.g., Europe, Asia, and Africa) using genetic markers that are known to be indicative of those ancestral groups. On average, the African Americans in the study had about 84% African ancestry.
Cheng and Kao’s findings add further support to the idea that differences in disease rates across different populations can be partly explained by ancestry genetics. A previous study looking at <a href="https://blog.23andme.com/articles/the-ancestry-link-for-atrial-fibrillation-risk">atrial fibrillation (a heart rhythm disorder) in African Americans</a> also found that having more African ancestry correlated with higher odds of the condition. Most likely, correlations like these reflect variations in the frequency of many different genetic factors involved in disease. In a few cases, though, individual genetic factors can have greater importance. For example, in East Asians, who have some of the highest rates of esophageal cancer in the world, a specific genetic factor causing the “<a href="https://blog.23andme.com/articles/researchers-warn-that-physicians-need-to-ask-about-alcohol-flushing-to-reduce-esophageal-cancer-risk">alcohol flush</a>” reaction plays a direct role in the development of esophageal cancer.
Studies like this one highlight the complex interplay between ancestry and health in African Americans, the vast majority of whom can trace significant parts of their ancestry back to at least two continents. Combined with <a href="https://www.23andme.com/ancestry/recent/">DNA-based tools</a> that allow people to see their <a href="https://www.23andme.com/dna-ancestry/">ancestral breakdown</a>, health risk assessments that incorporate genetic ancestry may help make healthcare more personalized.

African Ancestry and Risk for Type 2 Diabetes

June 19th is <a href="http://worldsicklecellday.webs.com/">World Sickle Cell Awareness Day</a> and commemorates the date in 2008 when the United Nations began recognizing this group of genetic blood disorders as a public health concern.
Sickle cell disease affects millions around the globe and nearly 100,000 people in the United States. It’s relatively common in Latin America, the Caribbean, Saudi Arabia, India, Mediterranean countries, and especially prevalent in those with ancestry tracing to sub-Saharan Africa. In the US roughly <a href="https://www.cdc.gov/ncbddd/sicklecell/data.html">one in 500</a> black or African-American babies is born with the disease. 

<div style="float: right; text-align: justified; width: 285px; background-color: #eee; padding: 15px; margin-left: 10px; font-size: 11px;">
<h6>Geno Atkins and Sickle Cell Trait</h6>
<img decoding="async" class="alignright size-thumbnail wp-image-13872" title="Geno_Atkins" alt="" src="https://blog-api.23andme.com/wp-content/uploads/2012/06/Geno_Atkins-150x150.jpg" width="140px;" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/06/Geno_Atkins-150x150.jpg 150w, https://blogcms.23andme.com/wp-content/uploads/2012/06/Geno_Atkins-271x271.jpg 271w, https://blogcms.23andme.com/wp-content/uploads/2012/06/Geno_Atkins-372x372.jpg 372w, https://blogcms.23andme.com/wp-content/uploads/2012/06/Geno_Atkins-574x574.jpg 574w" sizes="(max-width: 150px) 100vw, 150px" />
In his two seasons in the NFL playing with the Cincinnati Bengals, defensive tackle Gene Renard “Geno” Atkins Jr. has shown few weaknesses, notching up 48 tackles and eight sacks.
But throughout his time on the field – not just professionally, but when he was a standout player in college and high school– Geno has played with what is called the “<a href="https://www.cdc.gov/ncbddd/sicklecell/traits.html">sickle cell trait</a>.”
While it isn’t full-blown <a href="https://www.23andme.com/topics/carrier/sickle-cell-anemia">sickle cell anemia</a>, the sickle cell trait can pose health risks for those who don&#8217;t know they have it. For instance, people with the trait may be more vulnerable to heatstroke and muscle breakdown as a result of strenuous exercise.  Geno hopes to bring attention to the issue and recently wrote about his own experience in a piece on the CDC website. Because testing isn&#8217;t currently in place for high school athletes, many play without knowing they are at risk.
“I was blessed to not suffer any side effects or have any health-related issues due to the <a href="https://www.cdc.gov/ncbddd/sicklecell/traits.html">sickle cell trait</a>,” Geno <a href="http://www.genostacks.blogspot.com/2010/09/sickle-cell-trait-and-athlete.html" target="_blank" rel="noopener noreferrer">wrote in his blog two years ago</a>. “I would urge parents, friends, and extended families of all Athletes participating in any sports or working out at a high level to have their Athlete tested.&#8221;
After he learned of his risk in college, both Geno and his coaches paid particular attention to whether he was healthy during practice and games.
</div>
<h6>Sickle Cell Trait</h6>
Prevalence of sickle cell disease in African populations is high due to the fact that many people with African ancestry carry a genetic mutation in the HBB gene that causes the condition. You need two copies of this mutation (one from each parent) to have the disease, but if you have just one, you have what’s known as “<a href="https://blog.23andme.com/2012/02/14/did-you-know-one-in-twelve-african-americans-has-sickle-cell-trait/">sickle cell trait</a>”.
This trait protects you from malaria which is why the mutation has become relatively common in sub-Saharan Africa, where malaria is endemic. Unfortunately, it also increases the risk that your child may be born with sickle cell disease if your partner also has one copy of the mutation.
<h6>One in 13</h6>
Roughly one in 13 African Americans carries a copy of the HBB mutation and the World Health Organization estimates that sickle cell disease contributes to 5 percent of deaths in children under 5 years of age in some African countries. World Sickle Cell Awareness Day aims to highlight and combat this public health burden.
Although improved access to care is needed to counteract some of the public health burdens, appropriate genetic screening could lower the rates of disease and/or equip families with knowledge about their chances of passing the disease to future generations.
<h6>Raising Awareness</h6>
To raise awareness about sickle cell disease, the Centers for Disease Control (CDC) is piloting a data collection system called the <a href="https://www.cdc.gov/ncbddd/hemoglobinopathies/index.html">Registry and Surveillance System for Hemoglobinopathies</a> (or RuSH) to find out exactly how many US individuals suffer from sickle cell disease and related red blood cell disorders like <a href="https://www.23andme.com/topics/carrier/beta-thalassemia">beta-thalassemia</a>. They are also addressing unmet needs in research, surveillance, and education.
So we ask you today – do you suffer from sickle cell disease or know anyone living with it? What about sickle cell trait – have you been screened for a mutation that you could pass on to your child? We welcome your comments on this important health topic and encourage you to also raise awareness about this disease.
Find out more about 23andMe&#8217;s Sickle Cell report <a href="https://www.23andme.com/topics/carrier/sickle-cell-anemia">here</a>.

Raising Awareness For Sickle Cell Disease

As the series <a href="https://www.pbs.org/wnet/finding-your-roots/" target="_blank" rel="noopener noreferrer">Finding Your Roots with Henry Louis Gates, Jr.</a> continues its 10-week run on PBS, The Blog will feature posts from 23andMe’s Ancestry Ambassadors featuring their own stories about using DNA to dig into ancestry.
By Shannon Christmas
<img loading="lazy" decoding="async" class="alignright size-full wp-image-12107" title="shannon's gp" src="https://blog-api.23andme.com/wp-content/uploads/2012/04/shannons-gp.jpg" alt="" width="220" height="278" />
African American genealogy remains a challenging jigsaw puzzle where half of the pieces seem irrevocably lost. Many families scarred by chattel slavery buried their pasts to distance themselves and their progeny from the horrors of bondage.
<h2>A Fractured History</h2>
Now, advances in genetics and Internet technology have unearthed some of the long-buried pieces of our significantly fractured history.
Uncovering some of those missing pieces for my family required an open mind. One of my paternal great-grandmothers, Katie Lee Davis of Warren County, North Carolina, inherited a revisionist version of our family’s past.
In her correspondence with one of my cousins, Grandma Katie identified her ancestors, wrote lovingly of her paternal aunts, and recalled never having known a former slave among her relatives. Yet in 2010, 16 years after her death, revelations about Grandma Katie’s ancestors began to tell a different story. 

<img loading="lazy" decoding="async" class="alignright size-medium wp-image-12109" title="gravestone" src="https://blog-api.23andme.com/wp-content/uploads/2012/04/gravestone-300x225.jpg" alt="" width="300" height="225" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/04/gravestone-300x225.jpg 300w, https://blogcms.23andme.com/wp-content/uploads/2012/04/gravestone.jpg 453w" sizes="auto, (max-width: 300px) 100vw, 300px" />
Marriage and death records from Warren County list Grandma Katie’s paternal grandparents as Henry and Lucinda Davis, an African-American couple about whom little else is known.
<h2>A Pedigree</h2>
However, in the summer of 2010, Ray, the husband of one of my father’s first cousins, emailed me a pedigree outline that omitted Henry’s name and replaced it with a Peter “White” Davis. The glaring conflict between the government documents I had examined and this new email raised questions.
Who was Peter “White” Davis? Was he really Grandma Katie’s grandfather?
The answers to those questions only heightened my curiosity. Ray reported that Peter “White” Davis, a slave owner formally named Peter Randolph Davis, allegedly sired many mulatto children with his slaves. According to one of Katie’s elderly distant relatives, Grandma Katie’s father, Richard D. Davis, was one of those mulatto children.
<img loading="lazy" decoding="async" class="alignright size-medium wp-image-12108" title="erasmuschristmas" src="https://blog-api.23andme.com/wp-content/uploads/2012/04/erasmuschristmas-222x300.jpg" alt="" width="222" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/04/erasmuschristmas-222x300.jpg 222w, https://blogcms.23andme.com/wp-content/uploads/2012/04/erasmuschristmas.jpg 225w" sizes="auto, (max-width: 222px) 100vw, 222px" />
Tracing Peter Randolph Davis’ lineage yielded another discovery. Peter’s maternal great-grandparents included a couple I had encountered in previous research: Captain William Green and Mary Elizabeth Christmas. Captain Green and his wife, Mary, were indirect ancestors of my great-grandfather, Richard Christmas.
<h2>A Warren County Planter</h2>
Richard Christmas’s paternal grandfather, Lewis Yancey Christmas, a wealthy Warren County planter and attorney, took two slaves as common-law wives. The first union produced 12 children, including my great-great-grandfather, Erasmus Christmas.
If the Peter Randolph Davis story was accurate, then my great grandfather Richard Christmas and my great grandmother Katie Lee Davis were not only husband and wife for 60 years, but 4th cousins once removed.
The possibility of a consanguineous marriage, though initially unsettling, provided an opportunity to verify this new paternity claim using DNA testing. Web-based DNA analysis tools allow one to search an individual’s raw DNA data file from 23andMe for runs of homozygosity and DNA segments indicating one’s parents shared recent common ancestors.
<h2>Cousin Test</h2>
Since my grandfather, the son of Richard Christmas and Katie Lee Davis had tested with 23andMe, the truth sat just a few keystrokes away. GEDMatch.com’s “Cousin Test for Parents” identified nine runs of homozygosity among my grandfather’s 22 autosomal chromosomes, amounting to more than 55 centimorgans (cM) of DNA, an amount that suggests his parents were at least 4th cousins.
A similar tool created by mathematician David Pike (<a href="http://www.math.mun.ca/%7Edapike/FF23utils/roh.php">http://www.math.mun.ca/~dapike/FF23utils/roh.php</a>) replicated the results. Richard Christmas and Katie Lee Davis shared a bloodline, proving that Peter Randolph Davis was Katie’s paternal grandfather.
<img loading="lazy" decoding="async" class="alignright wp-image-12111 size-medium" title="shannondoc" src="http://35.88.189.111/wp-content/uploads/2012/04/shannondoc-218x300.jpg" alt="" width="218" height="300" srcset="https://blogcms.23andme.com/wp-content/uploads/2012/04/shannondoc-218x300.jpg 218w, https://blogcms.23andme.com/wp-content/uploads/2012/04/shannondoc.jpg 473w" sizes="auto, (max-width: 218px) 100vw, 218px" />
In early 2012, I obtained a slave inventory from an estate file for Dr. Stephen Davis (Peter Randolph Davis’ father); the family of Henry and Lucinda Davis appears among the slaves listed.
Like so many former slaves, the paternal relatives with whom my great-grandmother spent her earliest years clearly sought to conceal their dark history to embrace a brighter future. But DNA illuminated how that past proved prologue.
23andMe provides genetic testing services for informational purposes; your results may or may not help you find or identify relatives or family members.
When not updating pedigree charts or mapping his chromosomes, Shannon Christmas is the founder and Chief Market Advisor/Design Strategist of The Christmas Collective, a strategic real estate and land use consulting atelier.

African American — Page 4