My brother and I have both been tested on 23andme. There are many people that show up at different relationships and I'm trying to understand how there can be large differences in predicted relationships. We are of Ashkenazi heritage and I've heard that can make relationships seem closer than they actually are. My brother and I do show up as brothers (48% shared), so it's not that.
One example is a person is predicted to be a 2nd cousin to me (81cm, 10 segments) but a distant cousin to my brother (43cm, 6 segments). We both share the same 10.5cm segment with this other person but I also share segments of approx 9, 11, 10, 12 that my brother does not, plus 5 in the 5-6 range. My brother has a 8cm segment with this person I don't have then four of 5-6cm that do not match mine.
So given I don't share any long segments with this person and the total is on the low side for 2nd cousins, could it be that the smaller segments that seem to have pushed me into a closer predicted relationship are just IBS and the person is really farther from me than 2nd cousin? Or do you think we are 2nd cousins and my brother just didn't happen to inherit enough of the same DNA segments from our common ancestor?
We have a family tree that only goes back 2 generation for the most part but know the names of our grandparents siblings and their descendants. Unfortunately we don't recognize the names as belonging to anyone in the family tree we know about. However most of the people that match as 2nd cousins to me or my brother are listed as distant cousins to the other brother. I'm trying to figure out if the predicted relationship of 2nd cousin is real and there is some unexplained people in our genealogy or if they are really more distant relatives.