Well...I can tell you that I found a mother and son (I'm her 2nd cousin once removed and he's my 3rd cousin) and our total percentage of match is slightly less than 2% (23andme's relative finder said we were both probable 3rd cousins). However, we all match just about completely on an X chromosome. The X my 3rd cousin got from his mother and the one I got from my father match very very closely. We have other matching segments of autosomal DNA but those are tiny segments in comparison to our X matches. Of course X like other sex-linked DNA (Y and mtDNA) is inherited intact from one parent of the other. The problem with X is figuring out (for females like me at least) WHICH of the 2 Xes came from which parent. My cousins' paper trail and mine prove out exactly where each one came from. If I ever had any doubt as to paternity (I didn't but just saying) the X match verifies it in this case. Joan In a message dated 5/19/2012 1:37:11 P.M. Eastern Daylight Time, odinaz@comcast.net writes: Therefore the cousin does not have the large chunk, but only parts - and not necessarily the SAME parts as from the common ancestor (because that part may not have come from the common ancestors line, but from the non-related partner in each generation).