Wednesday, August 26, 2009

A New VICK DNA Project

Until now we have limited our common VICK DNA research to a VICK Y-DNA project. Y-DNA is only one type of DNA, but it is the most effective for genealogical research. Only men have Y-DNA, so only men have been able to participate directly (women can recruit a male VICK close relative to test for them). Because men inherit Y-DNA from their fathers, only men who have an unbroken male VICK line can test their Y-DNA for VICK ancestry.

We now have the opportunity to expand our project beyond Y-DNA. The expansion will allow us to include women and those men who have a female VICK in their line to their last male VICK ancestor.

Like with computers, the power of DNA testing has increased dramatically while the price has fallen dramatically. We are now able to expand our project because testing that looks at all of the chromosomes has become cheap enough that a large enough portion of our DNA can be tested to find what are called Half Identical Regions (HIRs). While these HIRs (shown in light blue in the graphic on the left) are not as useful for genealogy as the results from Y-DNA testing, they offer at least the possibility of finding matches with people who share a recent common ancestor (that is within a few generations). These HIRs can help us find our VICK (and other) cousins.

We are each about half identical to our parents. So if we look at our chromosomes, we will see that our chromosomes are about half identical to each parent. The screenshot on the left above is a comparison of my 23 pairs of chromosomes to my mother’s.

To make this comparison my mother and I both had to be tested. I am fortunate that my mother is still living and was willing to be tested. Unfortunately, my father isn’t living, so that opportunity is lost. When you look at the screen shot you can see that all of my chromosomes are colored a light blue (with the exception of the Y chromosome and those areas shaded in grey because they weren’t tested). Since my mother is a woman she doesn’t have a Y chromosome for comparison.

The screen shot on the right above is a comparison of my son’s 23 pairs of chromosomes to my mother’s. As you can see he is about a quarter identical to her (which makes sense since he got about half of his DNA from me, and about half of my DNA came from my mother). Since my son got his X chromosome from his mother, his X chromosome won’t be half identical to my mother’s.

My son’s comparison to my mother illustrates that as DNA is passed down it isn’t shuffled like a deck of cards. There are whole blocks of DNA that stay together to form these HIRs. In fact, HIRs can stay together for several generations. Looking at the members of our VICK Y-DNA project, I would expect that Austin Lafayette VICK and John Edward VICK would have some HIRs because they are third cousins. I haven’t studied their pedigrees, but I suspect their most recent common ancestors in any of their lines are Richard5 (Giles4, William3, Richard2, Joseph1) and his wife Mary [ ]. If I am correct about their most recent common ancestors, then any shared HIRs would most likely have been passed to John Edward and Austin Lafayette from Richard5 and Mary [ ].

By comparing Austin Lafayette and John Edward with another closely related VICK who doesn’t share Richard5 and Mary as ancestors, we could then see if the three compared had HIRs. If they did, then their most recent common ancestor would be the most likely source.

Finding these HIRs could be helpful in identifying female and non-surnamed VICK male cousins. For those who don’t have Joseph1’s Y-DNA (or the most distant known VICK ancestor for the other clans) finding HIRs could help to show the likelihood of VICK ancestry and where to focus further research. In our expanded project, we would start building a web of HIRs. These HIRs could also be used in other projects that are based upon other non-VICK lines.

For those interested in deep ancestry, 23andMe provides men with their Y-DNA haplogroup, and both men and women get their mitochondrial (mtDNA) haplogroup. Beyond the ancestry features of 23andMe, there is also information on health and traits. You can see what 23andMe has to offer by going to 23andMe and setting up a free demo account. There is even sample data for the fictional Mendel family that you can use to see how 23andMe works.

I am looking forward to seeing where our expanded project takes us and to seeing what we can learn.

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