I have a number of matches of good size that start on the left arm of a chromosome and extend across the center on into the right arm. I thought that the matches from one arm of a chromosome were from one parent and those on the other arm from the other parent. Mary Lou

No, there are two copies of the chromosome, one from each parent, and each copy has its own centromere. The problem with segments that cross the centromere is that the centromere is snip-poor, so it is hard to be assured that it really is one uninterrupted segment. FTDNA and 23andMe differ on whether to count these as one big or two smaller segments. On 2/4/2012 9:04 AM, Mary Lou Ramsey wrote: > I have a number of matches of good size that start on the left arm of a > chromosome and extend across the center on into the right arm. > > I thought that the matches from one arm of a chromosome were from one > parent and those on the other arm from the other parent. > Mary Lou > > > ______________________________ > 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 [email protected] with the word 'unsubscribe' without the quotes in the subject and the body of the message >

Does it matter if the crossing match is on the X chromosome? Actually it's a match between grandmother, mother, and daughter. Same place, same size. Quoting tewilder <[email protected]>: > No, there are two copies of the chromosome, one from each parent, and > each copy has its own centromere. > > The problem with segments that cross the centromere is that the > centromere is snip-poor, so it is hard to be assured that it really is > one uninterrupted segment. FTDNA and 23andMe differ on whether to count > these as one big or two smaller segments. > > On 2/4/2012 9:04 AM, Mary Lou Ramsey wrote: >> I have a number of matches of good size that start on the left arm of a >> chromosome and extend across the center on into the right arm. >> >> I thought that the matches from one arm of a chromosome were from one >> parent and those on the other arm from the other parent. >> Mary Lou >> >> >> ______________________________ >> 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 >> [email protected] with the word 'unsubscribe' >> without the quotes in the subject and the body of the message >> > > > > ______________________________ > 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 > [email protected] with the word 'unsubscribe' > without the quotes in the subject and the body of the message > >