The importance of DNA testing siblings

This week I was contacted by a DNA match. She went on to tell me that her file was at GEDmatch and that we had in the range of a 4.7 generation match. The first thing I always do after being contacted by a match is to run their One To Many and then do a Find within page for my email address. I did this and found mine in the 4.7 range. Hit next....and surprise. Mom and my sister match her at 6.7. Of course this means that I need to run the One To One comparison for each of us to this match and see what is going on. Upon doing that for both Autosomal and X I can tell you why I match more than my sister matches.

My best guess is this. On Chromosome 4 that is a match from my Dad's side that my sister didn't get. On this portion of Dad's side I also match a Morrow/Sutton cousin. I should also note for later research that since my sister doesn't match this on this segment to the Morrow/Sutton cousin which is from my PGM side...that my sister on this segment of her DNA from Dad got the part that Dad got from his Dad(PGF). Ran the One to One of the Morrow/Sutton cousin and my DNA match and they also matched which I was 99% sure they would. My sister appears to match her on the end of Chr 4 but at less than 5 cMs so I believe that is noise from colonial lines. On Chromosome 5 you can see the smaller match at just under 9 cMs between my sister and Mom.....a segment which I didn't get.from Mom. If I had already identified which side of Mom's that I got this section along..I would know that my Sister got the one from the other side of Mom's lines since we do not match. Another clue is found with the 5.38cM match that both me and my sister share with this DNA match on the X. Mom doesn't match this and I tend to believe it is most likely from Dad's side.. If so ..this will provide me with more clues as the X has certain inheritance patterns. I have looked back along My current theory is that this line is from Dad's side and that this and the segment that I have on Chr 4 is from the Craigs and or Knox line as this line is one further down the Morrow/Sutton lines.

Things to think about....If my sister had been the only one who tested for my family we would have totally missed the Paternal connection and likely written the Maternal match off as being too far back. Thankful that my sister tested because while we have a good deal of matches in common we have more that we don't have in common than I thought we would. I guess when you get out beyond 3rd cousins that happens even in ones that are heavily colonial. Something else that is very interesting. This DNA match has mostly Canadian ancestry....could their be a Loyalist in there somewhere?

This shows how Mom's kit, Dad's phased kit using mine(Mine minus Mom's DNA) and my sisters kit all match the DNA cousin that contacted me.