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Famous DNA Review – Genghis Khan

// March 31st, 2009 // No Comments » // General

In 2003, researchers from around the world released a paper that suggested that 8% of all Mongolian males have a common Y chromosome because they are the descendants of Genghis Khan (See “The Genetic Legacy of the Mongols,” 2003, Zerjal, et. al.,American Journal of Human Genetics, 72: 717-721). The researchers examined the Y chromosome variability of over 2000 people from different regions in Asia and discovered a grouping of closely related lines. The cluster is believed to have originated about 1,000 years ago in Mongolia and its distribution coincides with the boundaries of the Mongol Empire.

Genghis Khan’s empire (he ruled from 1206–1227) stretched across Asia from the Pacific Ocean to the Caspian Sea and was reportedly extremely prolific. Khan’s son Tushi had as many as 40 sons. His grandson Kublai Khan is reported to have had as many as 22 sons,and perhaps many more. Together this family may have as many as 16 million descendants alive in Asia today. It is extremely important to note that until DNA can be extracted from Khan’s bones (which have never been found), there is no definitive proof that this Y chromosome cluster is actually descended from Genghis Khan.

When Family Tree DNA compared the markers in the paper to their database, they determined that the Y chromosome cluster belongs to Haplogroup C3 (M217+). Forty-seven samples in their database at that time exactly matched the markers identified in the paper. The company has summarized the marker results from the paper and have made that information freely available.

A newly released study from Russian scientists examined the Y chromosomes of 1,437 men from 18 Asian ethnic groups (AltaiKazakhs, Altai-Khizhis, Teleuts, Khakasses, Shor, Tuvinians, Todjins, Tofalars, Soyotes, Buryats, Khamnigans, Evenks, Mongolians, Kalmyks, Tajiks, Kurds, Persians and Russians). The researchers discovered that approximately 35% of Mongolians possess the “Khan” Y chromosome. Surprisingly, the results of the study suggest that although the Mongol Empire held eastern Russia for 250 years, there are few “Khan” Y chromosome carriers in that region.
(more…)

To Sequence or Not to Sequence

// March 17th, 2009 // No Comments » // Science and Technology

To Sequence or Not to Sequence - That is the Question

An article appearing at Bloomberg.com, “Cheap, Detailed Genetic Testing Might Soon Be Ready for Market“, highlights some of the recent developments in DNA sequencing. The article is a response to three studies published at Nature Methods which reportedly “explore cheap technologies to decipher and analyze individual patients’ DNA by allowing researchers to quickly find the small portions of the human genome that make protein and describe them, while discarding irrelevant data.”

According to the author of the Bloomberg article, “complete” DNA sequencing for as little as $300 could be ready within months. Although it is unclear what the author means by “complete”, it is entirely foreseeable that SNP testing will soon be available for a reasonable price.

All this leads to the question which is so hotly debated in the blogosphere - if inefficient sequencing becomes available to the average consumer, should they get their genome sequenced?

As the article points out, there are already around 1,000 different DNA sequencing tests which range in price from $200 to $3,000. However, Cathy Wicklund, the president of the National Society of Genetic Counselors, believes that people should “think hard before asking for complete genome testing”:

“Just because we have the technology doesn’t necessarily mean that we should jump to offer it,” she said. “Consumers should ask themselves, `What is this going to tell me, is it going to give me information that’s helpful right now?’ ”

There are a number of strong voices in this arena, others who believe that genomic sequencing without further extensive studies that link genotype and phenotype is useless and potentially harmful to any consumer who does not have a strong genetics background. Although I respect this position, I believe that attempting to ward people away from genomic sequencing will prove to be ineffective. Genetics is about to leave the hands of the medical professional, and there’s nothing we can (or perhaps should) do about it.

Fortunately or unfortunately, the wave is coming. In just months or a few short years, anyone will be able to open an envelope or log into a website and see their entire genomic sequence, from the very first nucleotide to the very last. Thus the question is not whether people should get their genome sequenced - because they invariably will - but rather what can be done to educate consumers. With a background in genetics, I know better than many consumers all the dangers that my genetic sequence will reveal. But I’ll still be ready to swab my cheeks the instant I can afford a complete genomic sequence.

Is there really no proper place for the average non-geneticist, non-physician-assisted consumer in the whole genome market? What if I can’t afford a genetic specialist - should I be denied the opportunity to sequence my genome? What if my health insurer refuses to pay for genetic sequencing? Should only the knowledgeable or the rich be allowed to learn more about their genes?

I would argue that there is a place for the “early consumer.” Early consumers are the pioneers, the curious who do something because it is new and exciting and they want to learn more about the technology and about themselves. For instance, there are so many people that get into genetic genealogy even though they don’t know the first thing about genetics. When they get their results back, they do what the human mind was designed to do - they go out and attempt to learn more (and helping educate them is exactly why I started The Genetic Genealogist in the first place). Luckily, there are already others who are leading the consumer education front.

All new technology comes with risks. Even genetic genealogy, the sequencing of a few SNPs or a few 100 base pairs, can reveal unexpected or unwanted results. But should the risks really cause so much fear and caution? We are who we are regardless of whether or not we get sequenced. Sequencing just arms us with information that could, now or in the future, be useful. For me, the benefits far outweigh the risks.

In my opinion, the answer is to educate, educate, educate. Convincing people that their genome is scary or useless will dissuade very few from sequencing and will likely only alienate the pioneers.

Blaine T. Bettinger, Ph.D.

5 Reasons to Save Your Grandmother’s DNA

// March 12th, 2009 // 1 Comment » // Science and Technology

1. You got those big blue eyes from your grandmother, but chances are you inherited less desirable genes as well. We inherit our DNA from our parents, who inherited it from their parents. Since we all possess genes that can cause or contribute to disease, knowing one’s DNA and family medical history can be a great resource for someone who learns they have a genetic disorder.

2. Full genome sequencing is right around the corner! The X-prize quest for the $1000 genome will lead to efficient and affordable whole-genome sequencing. As commercial companies crop up and compete for customer’s business, leading to even lower prices.

3. Your grandmother’s DNA contains clues to her ancestry. X-chromosome, mtDNA, and autosomal genealogy tests contain clues to a person’s ancestry, both recent and ancient.

4. Even if you aren’t interested in this whole genetic genealogy craze, somebody you know will be! Genealogy is one of the most popular hobbies in America, and the use of DNA to augment traditional genealogical research is growing faster than ever. Chances are that someone you know will someday be interested in your
grandmother’s DNA!

5. All the undiscovered possibilities. No one knows what uses will be discovered for DNA in the future. Save that DNA just in case!

Disclaimer: Some people are very uncomfortable with the thought of gathering and storing a loved one’s DNA, and those beliefs should be honored and respected. It is ALWAYS best to obtain your grandmother’s permission before you gather her DNA. So don’t delay, call her now!