Margaret, No, I don't think so. I have 30 overlapping matches on Chr 8 between 106 and 127 Are the matches on large segments (23&Me uses 5cM as cutoff, FTDNA uses 7.7cM as cutoff, some advocate 10cM as a cutoff)? It they are smaller segments, most of us chalk it up to atDNA soup, not tied to any specific ancestor. If they are large segments, then count your self very lucky. If you can contact them, see how many of them relate to each other - if you get a 3-way match (each person has a match with the other two within the same large segment), then almost certainly the 3 of you share the same Common Ancestor. This is a relatively easy step that all adoptees should be taking - look for 3-way matches, or greater: if two can find a Common Ancestor the 3rd has a very strong clue. And in any case such a group can pool their information and look for place/time matches. If you match one other person and find a Common Ancestor, you don't really know for sure if the two events are connected - it could be a happenstance. I could probably find a Common Ancestor with almost anyone with real deep roots in Colonial VA (whether or not they tested DNA). But when 3 widely separated cousins all share the same atDNA segment, AND agree on a Common Ancestor - that's a very strong indication that the atDNA did come from that ancestor (usually, of course, our Common Ancestors are husband/wife couples - even if we don't know their names - and we don't know which one provided the atDNA). A 4-way is almost a guarantee. Another point you raise is about a lot of matches on the same segment area. If you take a single point on a chromosome, or some segment length that is common to all of the matches, there can be only two of your ancestors involved - one paternal, and one maternal. The atDNA you got from your Mom or Dad had only one of their ancestor's atDNA at that point - and that's it! Actually to get a little more technical, it's an "ancestral line" at any point on the chromosome - one person could match at one generation, and another person could match at one of their parents level. So pick any 7.7cM segment. Either your Dad or your Mom gave it to you - probably as part of a much larger segment. Let's say Mom. Well she got that segment from either her Dad or Mom; whichever one it was, that ancestor got it from one of their parents, etc. Until we get back to the earliest ancestor who had that whole 7.7cM segment - for that person, the segment was made up of smaller pieces from his/her parents - but we'll never know that because those segments were smaller that 7.7cM and those ancestors wouldn't pass the filter (actually the very distant living cousin/descendants of those ancestors whose small atDNA segments wouldn't pass the filter - so they wouldn't show up as a match). You could have a Common Ancestor at any of these levels, but always on the same ancestral line. Perhaps getting too deep - the bottom line is that at any Chromosome location - you have atDNA from an ancestor of your Mom AND atDNA from an ancestor of your Dad. A very valuable piece of information. So if you have 50 segments that overlap the same location on a Chromosome, some of them are from one maternal line, and the rest are from one paternal line. Memorize this! Jim Bartlett On 05/17/12, Margaret Waters<[email protected]> wrote: While playing with my data at GedMatch, I noticed that I had nearly 50 matches within a small range along chromosome 15. (I was using the Chromosome Segment Comparison.) This is way more matches than I have on any other chromosome and none so tightly bunched. Is this perhaps an area where many unrelated people might have the same segment lineup (or whatever the proper terminology might be)? Margaret