Paul, I am under no delusions. I have a long list of FF and RF atDNA matches; I email them and try to find a Common Ancestor. 37 of them and I have found a Common Ancestor, 5 of them at the 10th cousin level. As a genealogist, I am dlighted - we share lineages and records and other infomation. I also record the fact that we share a [usually one] large [over 7cM] segement of atDNA. I note the Chromosome and length and starting point. I put this in an excel spreadsheet along with my ahnentafel numbers leading up to the Common Ancestors [we can't really tell which one of the husband/wife team the atDNA came from]. I sort this by Chromosome and starting point, and manually look for patterns in the ahnentafel numbers. One a very few patterns so far. But as my database grows, I'll find more .... I don't yet know if the atDNA segment has followed the same path as the paper trail. I've researched a fairly robust family tree since 1974, but there are a lot of unknown ancestors in it. In the mean time, I know for sure, I have a paper trail to a Common Ancestor. That too, will need to stand the test of peer review, and someday, even more robust DNA tools. I'm looking forward to it. Jim Bartlett On 11/17/11, Paul Wright<[email protected]> wrote: It should also be noted that many of the smaller segments (under 7 cM) that are included and viewable at FTDNA and included in their total share algorithm may very well originate with a different ancestor than the one responsible for the larger (over 7 cM) segment share. As such, for individuals with less diverse ancestry, this along with the randomness of recombination, results in a tendency to predict many relationships as being more recent than they really are. Meanwhile a number of people who find any paper trial connection with a genetic cousin and automatically assume the shared DNA originates with that paper trial connection, may be mistaken and should be cautioned with regard to more distant relatives, unless they have a wider array of known and more recently related relatives to also compare and help walk them (and their genetic cousin) back to the common ancestor responsible for the largest segment share. The potential impact of unknown NPEs or what some theorize as shared DNA coming from very ancient common origins (i.e. middle ages and predate genealogical records) may imply additional uncertainty. On Thu, Nov 17, 2011 at 7:39 AM, Jim Bartlett <[1][email protected]>wrote: > > You can see down to 1cM segments at FTDNA, but when you contact a match, > looking to find a Common Ancestor, all of the FTDNA, and 23&Me, matches > have at least one segment that is 7cM long or more. Restricting myself to > FF and RF, I can't contact someone with only a 5cM long segment. > > > > ------------------------------- To unsubscribe from the list, please send an email to A[2][email protected] with the word 'unsubscribe' without the quotes in the subject and the body of the message References 1. mailto:[email protected] 2. mailto:[email protected]