Sunday, January 31, 2016

Three Siblings' DNA Chromosome Match Results

I previously shared the ethnicity estimates for me, my mother, and my brothers.

The following images from the chromosome browser at FamilyTreeDNA shows where exactly, on which chromosomes, my brothers and I match.

The first image shows my brother S's matches with me in orange and with my brother R in blue. In other words, I am logged into S's account and looking at where he matches me and R.

FamilyTreeDNA Chromosome Browser

The second images shows my brother R's matches with me in orange and with my brother S in blue. (Logged in as R.)

FamilyTreeDNA Chromosome Browser

The blue segments are the same in both images because they show where R and S match. However, you'll see that the orange is different in each example because I share different DNA with each of my brothers.

For example, look at chromosome 1 - I match my brother R on almost the entire chromosome (bottom image), but not with my brother S (top image). And on chromosome 6, I match my brother S on almost the entire chromosome (top image), but not that much with my brother R (bottom image).

I would love some known first and second cousins to test their DNA because I will be able to narrow down which ancestor has passed down which pieces of DNA to me and my brothers by where we all match (as seen on the chromosome browser). Ultimately I will be able to use this additional information to confirm how we are related to others who have tested their DNA and appear as cousins.

This brings me to the point about having siblings all test their autosomal DNA. We received different DNA from each of our parents so our DNA is different. This is seen at the chromosome level, displayed graphically in the images above. When I start to contact my family's DNA matches (and we have hundreds), it is possible that one sibling could share DNA with a more distant cousin, but the other siblings wouldn't share that DNA. As you see in the images and description above, there are segments where I match one brother and not the other and there are segments where my brothers match each other (and, of course, many segments where we all match).

I know this can be confusing, but it's also a very exciting new aspect of genealogy research once you get the hang of it.

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