"Not in common with" means that person X and person Y are not on each other's match list. FTDNA has a total cM threshold that one or both could fall below. That would be one of the possibilities. Barbara ----- Original Message ----- From: <AGilchrest@aol.com> To: <autosomal-dna@rootsweb.com> Sent: Wednesday, September 25, 2013 8:32 PM Subject: [AUTOSOMAL-DNA] Recombination question > > Hello > My father has a segment on chromosome 2 that is 17.09 cM total SNP 5500 > start position 47680185 end position 67921093 which matches person X. The > common ancestor couple has been identified. My father descends from one > of the > couples sons, person X descends from another son. My father and person X > are third cousins. > My father and I both match person Y on a segment that is within the above > segment. cM 9.17, total SNPs 3500. Start position 49442161 end position > 6179229. > Person X and person Y are not in common. My assumption here is that the > shorter segment is part of the other half of the pair of chromosomes. Can > I > make any other hypothesizes? Such as who this segment may belong to? Or > does recombination make this impossible? > Thank you, > Ann G. > > > ______________________________ > For answers to Frequently Asked Questions about mailing lists, please see: > http://dgmweb.net/MailingListFAQs.html > > > ------------------------------- > To unsubscribe from the list, please send an email to > AUTOSOMAL-DNA-request@rootsweb.com with the word 'unsubscribe' without the > quotes in the subject and the body of the message >