Thanks Ann, that is a very helpful calculator. Re: those suspicious results under discussion: >>>>> Sent: Friday, October 23, 2015 11:29 AM >>>> FTDNA >>>>> 9 131,456,657 137,335,024 8.85 1955 >>>>> >>>>> >>>>> gedmatch near identical boundaries and SNPs, but cMs are much larger: >>>>> 9 131,390,868 137,505,316 18.8 1,904 The Rutgers map interpolator gives the same result as gedmatch for the slightly longer gedmatch segment (18.8 cM), and gives a result of 17.8 cM for the FTDNA slightly shorter version of the same segment. These numbers seem consistent with what would be expected from the small difference in physical length (in base pairs). So the FTDNA estimate of segment length of 8.85 cM seems to be the suspicious number. I don’t have any explanations in mind for this. > On Oct 25, 2015, at 3:00 AM, genealogy-dna-request@rootsweb.com wrote: > > Date: Sat, 24 Oct 2015 16:03:42 -0700 > From: Ann Turner <dnacousins@gmail.com> > Subject: Re: [DNA] GENEALOGY-DNA Digest, Vol 10, Issue 578 > To: DNA Genealogy Mailing List <genealogy-dna@rootsweb.com> > Message-ID: > <CAA-Ub_CFQZjqshYa_2DKqZSJ2E1-qK95uxYdghqH4F=snsyZMA@mail.gmail.com> > Content-Type: text/plain; charset=UTF-8 > > You can enter base positions in this calculator. It's for Build 36, which > is used by FTDNA and GEDmatch. > > http://compgen4.rutgers.edu/mapinterpolator > > Ann Turner > > On Sat, Oct 24, 2015 at 12:43 PM, David Hamill via < > genealogy-dna@rootsweb.com> wrote: > >> Yes, the 10 cM difference (from 8 to 18) in such a small difference of >> physical length seems implausible. >> >> I calculated a 236,091 SNP difference in the physical length of the >> segments, and according to these results that total length is about 10 cM. >> >> I could not easily find anything online which maps different segment >> locations to length in cM, though I am sure it?s out there somewhere. >> >> It is just worrisome that the comparison makes it look like something is >> amiss. >> >> >>> On Oct 24, 2015, at 1:15 PM, genealogy-dna-request@rootsweb.com wrote: >>> >>> Date: Sat, 24 Oct 2015 11:51:26 -0400 >>> From: jlerch1@lighttube.net >>> Subject: [DNA] re FTDNA vs Gedmatch >>> To: genealogy-dna@rootsweb.com >>> Message-ID: <20151024115126.vush13734g4o08w4@webmail.lighttube.net> >>> Content-Type: text/plain; charset=UTF-8 >>> >>> To be specific, you're saying that there never can be a stretch where 10 >> cM is compressed into? 330,000 SNPs?? I don't know.? I know there are some >> pretty fragile spots.? On all my allegedly pileup spots, the middles which >> everyone shares is some unknown # but the difference between persons at the >> ends can be quite large, certainly 1 cM in about 100,000 SNPs. >>> >>> DHamill wrote >>> Subject: Re: [DNA] GENEALOGY-DNA Digest, Vol 10, Issue 576 >>> To: genealogy-dna@rootsweb.com >>> Message-ID: <14F5C288-84FF-4323-8A1D-93B5440D9B43@aol.com> >>> Content-Type: text/plain; charset=utf-8 >>> >>> I don?t think these results can both be correct. Not just a difference >> in criteria for a match or strictness of guidelines etc. If they really are >> reporting these results, I think there is something computationally rotten >> in Denmark. >>> >>> Maybe you could start by just double-checking these numbers.. just to be >> sure there are no typos etc involved? >>> >>> Does anyone else have a segment with about the same start and stop >> locations? ? if so how many cM? >>> >>>> On Oct 23, 2015, at 5:51 PM, genealogy-dna-request@rootsweb.com wrote: >>>> >>>>> -----Original Message----- From: Brooks Family via >>>>> Sent: Friday, October 23, 2015 11:29 AM >>>> FTDNA >>>>> 9 131,456,657 137,335,024 8.85 1955 >>>>> >>>>> >>>>> gedmatch near identical boundaries and SNPs, but cMs are much larger: >>>>> 9 131,390,868 137,505,316 18.8 1,904 >>> >