What is the Mutation Frequency Rate of mtDNA?

rw.gifAs I was reading through the GENEALOGY-DNA list from Rootsweb this morning, I came across a great question about the frequency of mutation of mitochondrial DNA (mtDNA).

The listmember asks “I am wondering if anyone would know the odds of having a mutation between my brother and me in our mtDNA. Marker 16163 is G for one of us and A for the other…” This is a great question, and one that I’ve been asked as well.

In response, Ann Turner writes “The mutation rate hasn’t been studied in the detail I’d like to see. The largest study for the hypervariable regions was based on deep-rooting pedigrees from Iceland. They found 3 mutations out of 705 transmission events.”

The study, available here (pdf, HT: Ann Turner) was conducted through deCODE Genetics and Oxford University. They used 26 Icelandic ancestral trees to identify maternally-related individuals, and sequenced 272 mtDNA control regions representing a total of 705 transmission events. The researchers found a total of three mutations, resulting in a mutation rate of 0.0043 per generation, or 0.32/site/1 million years. A previous study (Parsons et al., 15 Nature Genetics 363 1997) found a total of 10 mutations in 327 transmission events for a frequency of 2.5/site/1 million years, and yet another study found 2 mutations in 81 transmissions for a rate of 0.75/site/1 million years (Howell et al., 59 Am J Hum Genet 501). The huge differences in these numbers suggests that much more research needs to be done, probably with a much larger dataset. If I had unlimited funds, I would also be interested to see if there are different mutation rates among haplogroups, as well as a number of other factors.

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Genetic Genealogy From Around the Web

Although the world of genetic genealogy has slowed from the furor of November and December 2007, there is still plenty of discussion and consideration going on around the blogosphere.

First, Ann Turner , co-author of “Trace Your Roots With DNA” and moderator founder of the terrific Genealogy-DNA list has experimented with both deCODEme and 23andMe. Although she is still analyzing the results, she has a short write-up of deCODEme’s graphic presentations for comparing genomes (Word document here). The deCODEme comparison tool allows users to compare the degree of similarity between genomes, as long as the user has permission to compare. For those without a permissible genome to compare to, deCODEme provides reference samples from about 50 different populations. Ann points out that “it would be really interesting to hear if anybody is testing a number of close or distant relatives,” as their genome comparisons would be especially relevant.  Update: A revised version of Ann’s document with comparisons to more individuals is available here (zip file).

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The Genetic Genealogy Timeline

tiemline.jpgGenealogists spend many of their days (and much of their money!) tracking the history of their ancestors. They hunt through ancient records to elucidate even the smallest clue as to some facet of their ancestors’ lives. Since the majority of genetic genealogists started their journey as traditional genealogists, it is only natural that they enjoy record-keeping and tracking as well.

The DNA Genealogy Timeline is a free public resource maintained by Georgia K. Bopp and hosted by rootsweb.com. The timeline attempts to track the significant developments associated with genetic genealogy. It begins with “Before 1980″ and was updated most recently as of October 2007.

What immediately stands out is that genetic genealogy has been around much longer than people realize, especially given the recent media attention. I began my exploration of genetic genealogy in 2003, but by 2000 there were already as many as 4 surname projects begun by hobbyists! As of September 2007, one company (Family Tree DNA) had over 4,200 surname projects that contained more than 66,000 surnames. There are even more surname projects hosted by other companies, including Heritage DNA.

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Are You Thinking About Genetic Testing?

dna-stock_phixr.JPGIf you’re thinking about jumping into the field of genetic testing (whether for genetic genealogy or any other form of genetic test), you should be sure to do some research first. The results of any genetic test are incredibly personal, and can potentially have a huge impact. As a result, the decision to undergo testing should only be made after doing some vital research.

Luckily, a fellow DNA Network blogger has written a post that will help you do this important pre-testing research. Hsien at Eye on DNA has written “How to Prepare Yourself for a Genetic Test.” Hsien provides the following advice:

“Although you can’t change your DNA, it is possible to prep yourself for a DNA test just as it’s possible to prep yourself for a driving test. It is critically important that anyone undergoing DNA testing learn as much as they can about the results they can expect to receive, the interpretation of these results, and the impact results may have on their life choices.”

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Another Questionable Article About Genetic Genealogy

I honestly don’t know what to do with this next article. Meredith F. Small Ph.D., an anthropologist at Cornell University, wrote a brief article at LiveScience entitled “DNA Kits: Secrets of Your Past or Scientific Scam?” Dr. Small’s article is largely a comment on the article that appeared earlier this fall in Science, “The Science and Business of Genetic Ancestry Testing” (I provided an analysis of the article here at TGG).

According to Dr. Small:

“[The quest for identity] also leads unwary seekers of the past right into the hands of scam artists who claim they can trace anyone’s DNA back to its source.”

The sentence is extremely misleading:

First – a scam artist is by definition a person who engages in a “fraudulent business scheme.” Although genetic genealogy can be controversial, I’ve never heard a single customer accuse a company of running a scam. To the best of my knowledge, these testing companies are using the best science available to test DNA and compare results to their databases. Are physicians running a scam if they use open-heart surgery to fix a heart, rather than a simple pill that will be invented in 5 years? All technology is based on the best developed science right now. A company might have a limited database or only test a limited number of markers, but this does not qualify them as running a “scam.”

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A Repost – The $1,000 Genome, Part III

[This is a repost of an article that appeared on May 26, 2007. Since I’m knee-deep in final projects and exams, I thought I’d pull out a popular article from the archives. I hope you enjoy it (again)]:

In Part I and Part II of the “You and the $1000 Genome” series we examined the history of the Archon X PRIZE for Genomics and the success of the International HapMap Project. Today we’ll talk about some of the ethical issues associated with efficient and inexpensive genome sequencing. The value of whole genome sequencing will only be realized if individuals believe they have complete and legal control over their genetic information. I am greatly indebted to a thorough analysis of this issue by John A. Robertson at the University of Texas School of Law (”The $1000 Genome: Ethical and Legal Issues in Whole Genome Sequencing of Individuals (pdf).” 2003 The American Journal of Bioethics 3(3):InFocus). Note that this analysis is not intended to constitute answers to any of the ethical questions – it is only meant to be part of the discourse.

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A Repost – The $1,000 Genome, Part II

[This is a repost of an article that appeared on May 24, 2007. Since I’m knee-deep in final projects and exams, I thought I’d pull out a popular article from the archives. I hope you enjoy it (again)]:

In Part I of the “You and the $1000 Genome” series we examined the Archon X PRIZE for Genomics, a $10 million purse for the group that can sequence 100 genomes in 10 days for no more than $10,000/genome with an error rate below 0.001%. With today’s technology this goal is still a few years away.

But do we need an entire genomic sequence to obtain all the relevant medical information that our DNA contains? After all, 99.9% of my DNA is exactly the same as everyone else’s! Why sequence that 99.9% over and over and over if the results are the same every time? Wouldn’t it be cheaper to just sequence and then decode the 0.1%?

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Genetic Genealogy at the BBC

Megan Smolenyak of Roots Television (have you checked it out yet?) and Megan’s Roots World recently wrote a piece for the BBC’s Family History website, in association with their wildly popular Who Do You Think You Are? series.  “Genetic Genealogy – What Can If Offer?” is a great article for anyone who might be interested in learning about the opportunities and limitations associated with genetic genealogy.

And, you might see a familiar blog mentioned in the “Find Out More” section!

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A List of Books for the Genetic Genealogist

A lot of people write me to ask me questions about genetic genealogy, and a few have asked if there are any books on the subject that might help them learn more about it.  I thought I should provide a list of great reading material to help someone who might not have time to ask (but keep the questions coming!).

Great beginner books which are specifically about genealogy and DNA:

Trace Your Roots with DNA: Use Your DNA to Complete Your Family Tree by Megan Smolenyak and Ann Turner (Published October 7, 2004):

The Seven Daughters of Eve: The Science That Reveals Our Genetic Ancestry by Bryan Sykes (Published July 9, 2001):

How to Interpret Your DNA Test Results for Family History & Ancestry: Scientists Speak Out on Genealogy Joining Genetics by Anne Hart (Published December 2002):

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Dr. Kirk M. Maxey Shares his Expertise with Members of the DNA-NEWBIE Mailing List

The DNA-NEWBIE mailing list is a great resource for people who are new to genetic genealogy or genetic testing in general. The list provides a forum for questions while promoting education and the sharing of ideas. I primarily use the mailing list to follow current trends or concerns in the field of genetic genealogy so that I can share them here on the blog.

The recent deluge of media attention regarding J. Craig Venter’s diploid genome sequencing prompted one list-member to quote Dr. Edward Rubin: “It’s not clear whether it’ll be 10 years or 50 years, but in our lifetime, [individual DNA sequencing ] will happen.” The list-member goes on to say that it will probably not happen in his lifetime since he turns 75 next month.

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