Dear Jim, To me, the word "segment" implies a connected series of nucleotides, in other words a phased autosomal haplotype. An HIR is not a connected series of nucleotides. Therefore I cannot call an HIR a "shared segment". The genetic genealogy community is developing its own nomenclature here and I believe it is prudent to be labeling things as scientifically and as accurately as we possibly can. I have avoided calling HIRs "shared segments" in the past and I would recommend that other genetic genealogists do the same. When two people have a matching HIR they don't necessarily share a connected series of nucleotides. It is also important to note that just because two people have a matching HIR, it doesn't necessarily follow that one of the parents of the matches also has a matching HIR with one of the parents of the other match. Sincerely, Tim Janzen -----Original Message----- From: autosomal-dna-bounces@rootsweb.com [mailto:autosomal-dna-bounces@rootsweb.com] On Behalf Of Jim Bartlett Sent: Sunday, October 20, 2013 6:20 AM To: autosomal-dna@rootsweb.com Subject: Re: [AUTOSOMAL-DNA] Family finder matches what to make of them Tim, We are back to no standard definition of a shared segment. When the companies indicate we have a Match, it is with a person who has a shared segment with us - that is, we each have exactly the same segment. Now that segment which we share (the one upon which the match is based), may turn out to be IBD or IBS. I don't see where the term "shared segment" has been reserved for only IBD segments. We often don't know if a segment that is identical between two people, which we often refer to as our shared segment, is IBD or not. I note that you consistently use HIR for the segment between Matches, but many also use the term shared segment, because it is shared between two people who are reported as matches. It seems to to fit that meaning. Also I note that full identical region is used when two people match on both alleles over the length of the segment. This is typical with siblings - some of their atDNA comes from the same atDNA from both parents (whereas through recombination most of the siblings atDNA won't be identical). So if full identical regions refers to matching, both parents on a segment, I would think HIR means matching one parent on the segment. This would then mean HIR is the same as a shared segment which is IBD. That is an HIR has a string of alleles which matches one parent, which makes it IBD - the segment Descends from the parent. So does Half Identical refer to being identical to a parent; or being identical to a Match. In the case of being identical to one parent, then the possibility exists that a Match has an identical segment, but in his/her case it's an IBS segment. In the case of being identical to a Match, either or both could be IBS. I'd like to think that an HIR segment means it matches one of my parents. This is consistent with having at least one allele at each SNP match. If both alleles at each SNP match then we have a Full Identical Region. If we don't tie HIR to parents, and instead tie it to each Match, we would have regions where the one of our segments could be HIR with some Matches but not other matches. This would mean every segment is sometimes HIR and sometimes not - based on who we match. Jim - Sent from my iPhone - FaceTime!

Terminology is interesting.  In Tales from the Genome (the course 23andMe is sponsoring), Matt COOK (one of the instructors) said that nucleotides are really components of RNA while deoxynucleotides are components of DNA.  I found that interesting since we use the terminology single nucleotide polymorphism to describe changes in DNA alleles. Hopefully, I didn't add more terminology problems in my description. Regards, Larry ________________________________ From: Tim Janzen <tjanzen@comcast.net> To: autosomal-dna@rootsweb.com Sent: Sunday, October 20, 2013 1:52 PM Subject: Re: [AUTOSOMAL-DNA] Family finder matches what to make of them     To me, the word "segment" implies a connected series of nucleotides, in other words a phased autosomal haplotype.  An HIR is not a connected series of nucleotides.