Tuesday, September 30, 2008

My Genetealogy Dilemma - Blaine kindly responds

Last week I posted A Genetealogy Dilemma - Any Ideas? and Blaine Bettinger (The Genetic Genealogist) wrote an extensive comment to the post.

Yesterday, Blaine posted Identifying an Unknown Parent Using Genetic Genealogy in a more expansive response to my dilemma, and he provided cogent and helpful information. His response was:

"This particular situation is exceptionally challenging. If the child had been a boy, he would have his father’s Y-DNA and a decent chance at identifying his father’s surname (and thus could perhaps further elucidate his actual identity with the combination of DNA research and traditional genealogical research). If the unknown parent had been the mother, the daughter would possess the unknown parent’s mtDNA and a remote but possible chance of finding an mtDNA match and using traditional genealogical techniques to identify the mother."

And the possible long-term solution (I hope Blaine doesn't mind me using his quotes here, bolding and italics mine):

"I agree that AS OF TODAY, there is little to no hope that the woman will discover the identity of her father. However, people almost always believe that this mystery will never be resolved because there is no Y-DNA or mtDNA solution. Of course, as we all know, the child inherited 50% of her genome from her father. It is my hypothesis that somewhere in that DNA is a clue to her father’s ancestry which can ultimately be used to identify her father.

"How will autosomal (non-sex chromosome) DNA reveal her father’s identity? As genomic sequencing becomes cheaper and cheaper, it will be possible to sequence an entire genome relatively cheap (first under $1,000, then eventually under $100). With this technology, genealogical and medical organizations will use vast autosomal DNA and family chart databases to trace genes and mutations through genealogies. SMGF, for example, is already collecting both DNA and family charts, and is set to release the Sorenson Autosomal Database in the near future.

"Additionally, earlier this year a deadly mutation that leads to colon cancer was traced to an English couple that emigrated to the United States in 1630, almost 400 years ago. Although not everyone with this mutation is descended from this couple, many are; thus, if you have the mutation, it is very possible that you are descended from this couple and this would provide a clue to your ancestry that could be explored with traditional genealogical research. With cheap sequencing scientists and genealogists will be able to trace unimportant ‘quiet’ mutations through time and genealogies, just as scientists have already done with health-related mutations.

"So how will all this help the woman identify her father? Someday in the very near future she will be able to query her genome against a database of genomes and ancestries. Just as a deadly colon cancer mutation can be linked to a certain family, it is likely that the woman has one or more random mutations in her genome that are linked to certain families. Using traditional genealogical research (to rule out inheritance of those mutations through her mother, for example) and genetic technology, she might be able to use that knowledge to identify possible sources of half her DNA."

Blaine has additional comments about genetic tests and ethical concerns.

I thank Blaine for explaining the problem succinctly and providing a summary of the current state-of-the-art in DNA analysis. I hope he's right that it will eventually be possible to solve genetic genealogy problems like the one I posed.

I will pass Blaine's information to my CGSSD colleague.

By the way, Megan Smolenyak Smolenyak coined the term Genetealogy - see her Genetealogy web site.

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