Monday, August 27, 2012

IBS and Autosomal DNA?

Genealogy and Autosomal DNA may contribute to IBS (Irritable bowel syndrome) but this acronym has another meaning. Identical by state means your sharing a common DNA segment in your autosomal DNA is just a coincidence, and you are not actually related to the person. Too weed out some of these matches and find out whether you are actually related IBD (Identical by descent or you both inherit that segment from a common ancestor) we bring in another acronym SNP (single nucleotide polymorphisms) which are copying errors. If you share at least 500 SNPs, or over, on a segment of shared DNA than you are likely related or IBD. 
I went back to my Owens match to check whether we were IBD on the two matching segments. Yes we were. Both were over 500 SNPs

At gedmatch I was able to find cousins who shared a common ancestor at 11 and 12 generations back in Quebec. I noticed the segments I shared with them were IBD, but the segment sizes are generally in the 3cM range. I believe two where in the 5 cM range. This is just one example.

Our shared Ancestry which is back in the 1600's

So my learning process continues. 

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