Dear Patti, I believe that it is possible to sort issues out such as what you described using autosomal DNA analysis. However, you need to have enough people tested so that you can be reasonably certain about the conclusions that you draw from your analysis. You might want to review the analysis that I did at https://blog.23andme.com/ancestry/who-were-the-parents-of-jacob-youngman. This is similar to the type of analysis that you will need to do. In your case, the closest possible relationship between the great grandson of Robert Purtell and you is 2nd cousin once removed. Your uncle could be a 2nd cousin of great grandson of Robert Purtell. In the case of 2nd cousins you would expect about 220 cMs to be shared between the two people involved and for 2nd cousins once removed you would expect about 110 cMs to be shared between the two people involved. If you aren't seeing the total cMs shared between the people involved using the chromosome browser at 23andMe then this would suggest that the genealogical relationship is more distant. Testing more people from various lines of descent can help you better determine the probable genealogical relationship, particularly if the genealogical relationship is more distant than 3rd cousins. Sincerely, Tim Janzen -----Original Message----- From: genealogy-dna-bounces@rootsweb.com [mailto:genealogy-dna-bounces@rootsweb.com] On Behalf Of Patti Hacht via Sent: Saturday, December 19, 2015 7:11 PM To: genealogy-dna@rootsweb.com Subject: [DNA] Three brothers from 1800's and recent DNA matches. I have a question regarding three Irish brothers. For forty plus years I have been researching my Purtell line from near Kilcolman (Shanagolden area) of Co Limerick, Ireland. I discovered my 2nd gr-grandfather, John Purtell b cir 1816 probably in Kilcolman parish. In the Kilcolman Parish rcds, I find a Laurence Purtell who was the sponsor in several of John's children's baptisms. I have thought that Laurence might be John's brother as he was born abt 1810. Laurence emigrated to Binghamton, NY about 1849. About a year later, my John followed Laurence to Binghamton, NY. Within four years, my John had moved further west to Michigan. Then there was a Robert Purtell, said to be related somehow to my John. Robert was born abt 1808 (probably Kilcolman) and emigrated to LaSalette, Ontario, Canada in the 1840's. Members of Robert's family eventually made their way to Midland, Michigan. Enter DNA testing. My brother and my Uncle (who's mother was a Purtell) both DNA match the great grandson of Robert Purtell from LaSalette. (My sister and I do *not* match the LaSalette Purtell's.) And now my brother and "Purtell" uncle also match a descendant of Laurence's from Binghamton. My question is, is there a way (using our DNA matches) to figure out if Robert b 1808, Laurence b 1810 and John b 1816 might have really been brothers? Patti in Lakeville, MIchigan