Why We Need Gedmatch!

I don’t blog often but I felt that I needed to get the following off my chest, so to speak.

There are three main autosomal DNA testing companies for genetic genealogy: AncestryDNA, 23&Me and Family Tree DNA. Gedmatch.com is a free website where people who tested with any of the three companies mentioned above, can upload their autosomal DNA results. It offers tools for analysing DNA matches.

Upto 2015, AncestryDNA did not mail kits to Ireland (or the UK) so people in Ireland tested with Family Tree DNA or 23&Me. As Family Tree DNA uses cheek swabs unlike 23&Me which uses saliva, it worked out cheaper to mail kits to Family Tree DNA rather than to 23&Me so I suspect more Irish people used Family Tree DNA than 23&Me, unless they tested for medical reasons. AncestryDNA and 23&Me have large autosomal databases while Family Tree DNA’s database is significantly smaller. However, figures have been presented  at the WDYTYA in Birmingham  in 2015, to suggest that about 90% of 23&Me’s testees and about 99% of Ancestry.com’s testees are based in the USA while just 70% of Family Tree DNA’s testees are based there. So, there are advantages and disadvantages in all three companies depending on your requirements. Note, these figures will change with time!

Several members of my family, including my father, who is now deceased have done autosomal DNA testing with Family Tree DNA. I also know many Cork people who have tested with Family Tree DNA. This year, I was lucky to be given a complimentary AncestryDNA kit when the company launched its sales in Ireland so I now have tested with both Famly Tree DNA and AncestryDNA.

In order to see which of my matches on AncestryDNA also match my late father, I have to try to get these matches to upload to Gedmatch.com as retesting my father with AncestryDNA is not an option. Also, paper trails are not enough to help analyse these matches especially as my father’s maternal side, albeit Irish (Co. Cork), is largely unknown. Secondly, it is DNA testing and is not meant to rely on paper trail analysis only! There is no chromosome browser or information on the number of centiMorgans involved in the matches on AncestryDNA so I cannot analyse the data involved. It is like a black box!

On Family Tree DNA, I can see which people have matches in common with me (ICW) and I can see if they match each other (matrix) but I cannot triangulate these matches to check: if A matches B and C on one segment of a chromosome, that A also matches C on the same segment of chromosome. This is a vital component for analysing matches to see if there is a common ancestral line for A, B and C.

I have to state that I don’t have any experience of 23& Me to add to the above comments.

Recently, I couldn’t convince someone to upload their autosomal DNA from Family Tree DNA to Gedmatch.com so I paid the $39 for someone of interest to me, who had tested with Ancestry.com, to transfer his results to Family Tree DNA. This helped me to see if the two people of interest to me matched each other. In fact they didn’t but now I know.

Recently,  I convinced an adoptee, who had tested with Ancestry.com to upload to Gedmatch.com. This confirmed that he matches me on my paternal line and also my maternal line, something I couldn’t tell without using a chromosome browser and triangulation facilities. So, this match which Ancestry.com predicted to be a third cousin is probably not quite as close as predicted, given that we match on both sides of my family. It really helped the adoptee to know more about his matches with me and other members of my family.

Another case which comes to mind,  involves a match which I have on Ancestry.com. I convinced the person who matches me, to upload to Gedmatch.com and now I can see that that person matches me on both my maternal and paternal lines. Now I want to know if this person matches someone else on Family Tree DNA who matches me but I can’t convince that person to upload their results to Gedmatch.com so I am trying to get the person who has tested with Ancestry.com to transfer their data to Family Tree DNA (for $39) as well as having convinced them to upload to Gedmatch.com.

Yet another match of mine on AncestryDNA will not communicate and this match is in common with two of us who are struggling to identify certain ancestral lines. We know the match is in common with us as we invited each other to see each other’s results. This is useful on AncestryDNA but I imagine it is not widely used. If we could see our matches with this person of interest, on Gedmatch, we could learn a lot more our matches. It is frustrating!

So, in general, Gedmatch.com is a free “neutral” site with useful analysis tools for autosomal DNA results. Gedmatch. com is free but does need support in the form of donations. I would encourage as many people as possible to upload their autosomal DNA to Gedmatch.

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