DNA from a lock of hair
Reader John Henning asks:
I’ve come across some locks of hair from my great-great grandmother that were in a scrapbook of my grandmothers (and actually from several of my grandmother’s friends from the 1920s/30s). This sharing of hair apparently was a ‘thing’ back then. Anyways — is there a benefit for having ancestors’ hair tested for DNA analyses? I am still very new to genealogy in general and even more green at the ins and outs of DNA.
It’s absolutely possible to get DNA from a sample of hair. Scientists have used hair from ancient and aboriginal remains1 and even from a woolly mammoth2 to obtain DNA for testing. But that doesn’t mean you should go ahead and test that lock of hair from your great-great grandmother, because hair poses some problems in terms of what DNA you can get.First and foremost, understand that there are two key parts of a hair for DNA purposes. If you look at the graphic shown here, you see that there’s a lot more to hair under the skin than there is in the part you can see. No matter how long the hair shaft is — the part that you can see — it has much less genetic information than the part that’s under the skin.
For DNA testing purposes, the part you really want is the hair follicle — and that’s the part that’s least likely to be included in a preserved lock of hair.
There are essentially three types of DNA testing. The first is Y-DNA, testing the male-gender-linked Y chromosome for information that’s passed in a direct line from father to son to son.3 The second type is autosomal DNA (or atDNA), which tests DNA from all of the chromosomes except the gender-linked X and Y chromosomes, and that’s tested for information that can help link cousins across genders.4 And the third is mitochondrial DNA (or mtDNA), which tests for information that’s passed in the direct female line, from mother to her children but can only be passed on by a daughter.5
Both Y-DNA testing and autosomal testing involve nuclear DNA (DNA from chromosomes inside the nucleus of a cell) while mtDNA involves the mitochondria, which exist outside of the cell nucleus.6 And a hair shaft simply doesn’t contain nuclear DNA.7 In other words, you can only do one of the three types of DNA testing on a lock of hair that doesn’t have a root or follicle attached, and that’s the mtDNA testing.
That’s problem number one — only one test you can do at all: the test for your great great grandmother’s maternal line (her mother and grandmother and so on back into time). Of all the types of DNA testing, that’s the one that’s typically least useful for genealogical purposes.8
Problem number two is the age of the sample. Now obviously if folks can test samples from a woolly mammoth — a wee bit older than any sample from anybody’s great great grandmother! — these hair locks may be tested successfully too. But remember that teams of scientists worked on those old samples, and you’re probably not in a position to pay the salaries of teams of scientists to do the types of forensic testing that may be required. So even if you decide to go ahead, remember that it may not be successful absent very expensive advanced testing.9
Problem number three is that finding a lab to do the test for you is a little more complicated that ordering a kit from Family Tree DNA or 23andMe. At this point, and certainly for the foreseeable future, none of the usual genealogy DNA test companies will do hair testing.
So you’re automatically going to be dealing with a commercial lab, and not every commercial lab will work with hair samples. They’re all going to want to know how much hair you have and how old it is before they’ll give you a quote,10 and you’re definitely going to want to shop around before settling on a lab to do the work. Asking around on the mail lists run by genetic genealogists would be a good way to start — there’s a DNA Newbie list for members of the International Society of Genetic Genealogists, for example, and it’s free to join.
Clearly, then, you’re going to want to carefully review whether you have another easier way to get the same information. Is there a person living now who’d be willing to do a current mtDNA test who is a descendant of your great great grandmother in a direct line (your great great grandmother to one of her daughters and on down to today)? Remember that every child has his or her mother’s mtDNA11 so the person tested can be male or female as long as that person’s mother descends in a direct female line from your great great grandmother.
If there is such a person, it’ll be easier and cheaper to simply test that person’s DNA. But if there isn’t such a person, then if you can afford it and if you’re are willing to take the risk of paying for a test that may not work, I’d at least consider it.
Good luck! Let us know how you make out!
Image source: Wikimedia commons, public domain image by Tsaitgaist
- David Perlman, “Hair DNA reveals 2 migration waves out of Africa,” San Francisco Chronicle online, 23 September 2011 (http://www.sfgate.com/ : accessed 2 Jun 2012). ↩
- Melissa Lee Phillips, “Hair yields ancient DNA,” The Scientist (http://classic.the-scientist.com : accessed 2 Jun 2012). ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Y chromosome DNA test,” rev. 23 Jul 2011. ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Autosomal DNA,” rev. 8 Feb 2012. ↩
- See “Understanding your mtDNA Results,” Family Tree DNA (http://www.familytreedna.com : accessed 2 Jun 2012. ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Mitochondrial DNA,” rev. 30 Jul 2010. ↩
- “Hair Analysis,” WebMD.com, 12 Apr 2010 (http://www.webmd.com : accessed 2 Jun 2012). ↩
- See generally Oh, mama… a use for mtDNA, The Legal Genealogist, posted 12 Feb 2012. ↩
- “How Can I Do a Hair DNA Test?,” Science on Stage: A Programme for European Science Teachers (http://www.scienceonstage.net : accessed 2 Jun 2012). ↩
- See e.g. “Information about Non-Standard Samples for DNA Testing,” Easy DNA (http://www.hairdnatest.com : accessed 2 Jun 2012). ↩
- ISOGG Wiki (http://www.isogg.org/wiki), “Mitochondrial DNA Test,” rev. 23 Jul 2011. ↩