Tuesday, August 08, 2006

DNA Article Ratings: 7.5, 6.0, 8.5 and 5.0

Lately there's been an epidemic of articles about genetic genealogy in the mainstream press. Those of you who read this blog know that I've taken to rating these articles -- partly because they have a tendency to be less than accurate.

In a sense, it's not the fault of the writers. They're expected to absorb and report on a topic that takes a little time to truly master -- and they have to do this very quickly and under strict word limits.

I've started rating articles not to be a "critic" in the classic sense. In point of fact, I'm delighted that all these folks are writing about genetealogy! I just thought it would be a good idea to bring attention to these articles (unless you live where they're published, you might not even be aware of them) and to help clarify some of the misunderstandings that crop up.

So here we go with the latest batch . . .

Students take part in ancestral study
I'm giving this one a 7.5, but first, I have to confess a bias. This article is about high school kids taking tests from National Geo's Genographic project as part of an effort to learn more about DNA and see how it applies in their own lives. I love this -- especially because I'm still smarting from a review of the book I co-authored with Ann Turner, Trace Your Roots with DNA. The review appeared in The American Biology Teacher and concluded, "This book is a wonderful and interesting read, but I feel it has limited usefulness in the classroom." Ouch!

So it's no surprise that I'm pleased to see an article that promotes the use of genetealogy as a means of sparking kids' interest in genetics. Having said that, I have two minor quibbles.

First, the article states, "New DNA studies suggest that all humans descended from African ancestors who lived 60,000 years ago, National Geographic reported on its Web site." Well, the writer has it half-right. She's alluding to what's sometimes referred to as the genetic Adam and Eve, our most recent common male and female ancestors. But in this case, 60,000 years pertains only to this Adam, who is estimated to have lived about 60-65,000 years ago. The genetic Eve is believed, by contrast, to have lived roughly 140-150,000 years ago.

Also, the articles says, "The latest DNA research has found that most genes that are passed from a mother and father to a child are mixed up." Well, this isn't exactly the latest DNA research. What she's talking about is autosomal DNA, the kind that's shuffled at each birth event, as opposed to Y-DNA and mtDNA, the types most heavily used for genetic genealogy.

So a pair of tweaks, but fortunately, they don't heavily affect the accuracy of the rest of the article, so that -- and my personal bias! -- are why I'm giving it a 7.5.

DNA helps identify distant ancestors
Randy Seaver's already shared some remarks on this article in his blog and he's not too keen on it. After reading it, I'm giving it a 6.0.

OK, let's break it down:
  • There's a person quoted as saying that genealogy is the number 1 hobby in the country. That's an exaggeration, but it's a quote and I can easily believe that someone said this.
  • It then goes on to say that "the practice of using DNA in genealogy was started in 2000 by the Family Tree DNA . . ." Close, but not quite. Family Tree DNA was second to market. Oxford Ancestors in the U.K. was first. (Also, I'm not sure why, but the writer keeps saying "The Family Tree DNA," just as many folks tend to say "The Ukraine." It's quirky, but doesn't really affect accuracy.)
  • The article mentions the Southern California Genealogical Society "which is also affiliated with the organization," the organization being Family Tree DNA (FTDNA). While it's true that SCGS folks are big fans of FTDNA, I don't know of any formal affiliation.
  • Next comes a remark that Randy thinks is far-fetched: "Miller predicts that within 10 years DNA technology will be able to tell people what family line they are related to - before they do any other research." In the interest of full disclosure, I have to point out that I know Doug Miller, but that doesn't influence what I'm about to say -- because, in a sense, I've been saying it longer than Miller. I've been saying for several years that in the not-too-distant future, genealogical newbies will start their research with a DNA test -- or at least, take one very early in their research. And in point of fact, this is already happening with the Genographic project where all sorts of folks who previously had no interest in their roots are getting into genealogy because of the DNA test they took via National Geographic's project. DNA testing is really good at telling you to "look over here" and "don't even waste your time here." It doesn't solve your mysteries (well, sometimes it can), but much like the Internet, it helps you go further faster. Also, what I suspect Miller is alluding to here is what we might be able to learn in the future by combining results from a combination of tests -- particularly from Y-STR and Y-SNP tests. So overall, I agree with Miller's remarks more than I disagree with them.
  • Randy also points out some confusion over a mini-case study given that involves a man named Yung searching for his Chamberlain roots. The writer doesn't take the time to clarify, but Yung was undoubtedly tested by proxy by some Chamberlain cousin of his since his own Y-DNA would represent his Yung family. And yes, the remark that, "He turned out to be a perfect match, so now I can trace my lineage all the way back to 1535 in North Cadbury, where there are still relatives," is certainly an exaggeration. This kind of testing can tell two people that they share a common ancestor, but it can't say who that ancestor is or exactly when he lived. So this is a bit of a stretch, but whether Yung was misquoted or whether he was just so gung ho that he elevated the power of this testing is hard to say.
  • Finally, this closing remark by Doug Miller is curious: "It's well-established science that we're all related to the same black man and woman out of Africa about 200,000 years ago," Miller said. "I've had some people get angry at me for telling them that in my DNA seminars. It's a very touchy subject." Please refer to the comment I made earlier about genetic Adam and Eve, but it's true that it's a touchy subject. I deal with this in some of my talks and it really comes down to personal belief systems, but scientifically, yes, the gist of this is true.
My primary concern with this article is the impression it leaves that a pair of Y-DNA tests can identify a common ancestor, rather than just confirm the existence of such a person. And that's why I'm giving it a 6.0.

A chip off the auld sod
This is one of the better articles I've read, so I'm giving it a whopping 8.5. It includes a couple of case studies, but also offers the proper cautions -- one of them coming from Bennett Greenspan, the head of Family Tree DNA. My only gripe on this one has to do with one of the people interviewed who claims that Ukrainian and Polish roots are about impossible to research. This person took a BioGeographical test to help break this alleged impasse. Well, as an individual with roots in Ukraine, Poland and Slovakia, I can tell you that it's not anywhere near impossible to research this kind of heritage. In fact, I find it much easier than my Irish side. And expecting the BioGeographical test to shed much light for this set of circumstances suggests that the test-taker didn't really understand what it could and couldn't reveal. But I believe that the writer accurately captured what was said. In fact, it's pretty typical of the unrealistic expectations that many articles create (by glossing over important nuances) -- and that I then encounter when I go out and speak to folks about genetealogy. And for that reflection of reality alone, I really like this article.

DNA offers avenue to black ancestry
I found this article somewhat frustrating. First, it sort of leaves the impression that certain realities are just hypothetical, such as the notion that mtDNA is passed from mother to children down through the generations. And of course, it cites the only known exception that's ever been encountered as sufficient reason to doubt all this. Also, it leaves the reader with an impression that mtDNA is somewhat more useful than Y-DNA, while the reverse is actually true. Yes, mtDNA was used for 9/11 identifications -- because it's resilient and more likely to survive in degraded remains, not because it's better than Y-DNA for identification purposes.

But what irked me most about this article was the following:

"What worries me most is people overselling the technology,” said Hank Greely, a Stanford University law professor and bioethicist. "I don’t think it can accurately give people the details they want." The article continues, "Greely said results showing just one-sixteenth of one’s heritage can be misleading. What if the other fifteen-sixteenths are completely different?"

This is the old, hackneyed objection that we used to encounter back in 2001 and 2002 -- an academic who thinks that those of us doing genetic genealogy are too dense to understand the fundamentals, such as the fact that a test only represents one branch of our family tree. And if you're going to use this tired claim, what is it about great-great-grandparents that makes you stop there? Why does a test supposedly only represent 1/16th of your heritage? Why not make it great-great-great-grandparents, 1/32nd? or great-great-great-great-grandparents, 1/64th? And so forth. These tests don't represent 1/16th of your heritage -- they represent one branch. So if you're concerned about others' inabilities to grasp the basics, master them yourself first! (There, I feel better! Sorry for that little outburst, but I battled that particular objection for several years, and am just frustrated to see it rise from the ashes.)

And if you want to challenge these tests, why not raise the more legitimate issue that many who take African Ancestry tests wind up matching folks in several locations in Africa? That because Africa is the cradle of mankind, we've had longer to migrate there than anyplace else, so it's a little on the optimistic side to expect that your genetic signature (whether Y-DNA or mtDNA) will be found in only one location on the continent?

Then the article goes on to note that other companies have sprung up in recent months to address other ethnic groups, such as Trace Genetics which provides Native American tests. Trace Genetics has been around for several years -- in fact, long enough that they were actually absorbed by DNAPrint Genomics about a year ago.

Finally, the article concludes with some remarks by Tony Burroughs, noted professional genealogist, who points out that DNA tests are not a panacea and that they don't replace the need for traditional research. This, at least, I can get behind. But overall, I found this article flawed, so I'm giving it a 5.0.

And so ends today's genetealogical rant! If you actually made it this far, thanks for your patience!


At 11:45 PM, Blogger Randy Seaver said...


Yep, I made it to the end...great rant! I learn a lot every time you rant, er, write something about genetealogy (did I spell it right? darn, can't go look).

I have a question about the testing services. If I had a 37-marker Y-DNA test done say by FTDNA, will I be able to compare the results with folks who have it done by another testing service? In other words, do the testing services use the same exact markers, or are they different, and therefore you can only match with folks who have it done by the same testing service?

Thanks -- Randy

At 11:31 AM, Blogger Megan Smolenyak Smolenyak said...

Hi Randy,

Each testing company has its own favorite markers, but there's heavy overlap, so you'll be able to compare most of the markers with folks tested elsewhere. Check out ybase.org, ysearch.org and smgf.org -- all places you can play the matchmaking game, regardless of which testing company you used. And BTW, as a customer of FTDNA, you can automatically upload your results to ysearch.

Take care,


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