Question for those who also use Genome Mate

[jsarnacki]

OK, so my mom's kit's chromosome browser FINALLY works! I recently downloaded Genome Mate and am beginning to sort through the "relatives" and am trying to figure out who might match on maternal and paternal sides. There are some I already figured out where we match and am putting that in the notes section.

Just for reference, I have tested myself, my husband, our 3 children, and both MY mother and father (his are deceased although we might someday get access to his mother's 23andme results if we can ever get his sister to access her account (theirs are linked together). I also have my husband's mother's half sister as a match to help sort out HIS matches. Oh, and I should have my paternal grandfather's dna soon hopefully. Anyhow, I am researching both my family and my husbands (for my kids), but my primary focus is my own family since I have a lot more information on my family history.

Anyhow, with MY matches... I have gone through them and put Maternal or Paternal accordingly, for shared segments with either my mother or my father. There thankfully are no shared segments for relatives that match both my mother and father, but there ARE many that don't match EITHER my mother or father. So... my question is... are these matches more likely to be false matches? There seems to be a lot of them on a couple chromosomes especially in certain spots. These matches are 7-9cM's. I haven't looked closely yet to see if they do match on OTHER chromosomes yet, but I don't think they do. If they are NOT false matches... what might attribute to them not matching either or my parents? Just DNA recombination or something?

Thanks!

[dna]

I would say: perfect IBS.

Mr. W.

[prairielad]

Not sure about other companies, but FTDNA matching criteria seems to require a minimum on 20cM of DNA in Total to be shared to be declared a match. Plus a few more..

Now for you and these matches, it is probably finding multiple IBS segments by creating small segments by using both your maternal and paternal values plus the longest segment (IBD segment).

These longest segments (over 7cM) will most likely be found in one of your parents, but since these segments plus IBS segments between them and these matches do not total 20cM in shared DNA, They are not declared a match.

If these match and yourself use gedmatch and you compare your parents files to them using the one to one compare, you will most likely see this longest segment in one of them.(setting SNP count to 500 and cM length to 5cM)

[K. L. Adams]

I would say: perfect IBS.

Mr. W.

Identical by state or identity by state (IBS) is a term used in genetics to describe two identical alleles or two identical segments or sequences of DNA. The terms identical by type or identity by type (IBT) are sometimes also used. In genetic genealogy the term IBS is generally used to describe segments which are not identical by descent and therefore do not share a recent common ancestor. IBS is also used in genetic genealogy to describe small IBD segments which are shared by many people both within and between populations and which have no genealogical relevance.

The techniques of triangulation, chromosome mapping, and phasing can be used to distinguish between IBD segments and non-IBD segments.

http://www.isogg.org/wiki/Identical_by_state

[jsarnacki]

Thanks. I played around with it for a while and wound up deleting the database info and starting over. Luckily I am early enough into this that I can do that! I tried changing the import threshold to 20cM and that seemed to eliminate too much data, so I settled on only importing those with 15cM or more matching DNA. I think even changing the setting to 10cM eliminated a lot of those "matches" that didn't also match either of my parents. Hopefully this leaves me with a better starting point on the database to sort through data.