I had the YDNA and mtDNA down pretty good in my head. One is paternal, one is maternal, and so on. Then after I submitted my info to GEDMatch, I saw the “Compare your X-chromosome FTDNA or 23andMe result with one other result in our database” option. Ok, so what exactly does the X Chromosome tell me and how do I inherit it?
The X Chromosome is passed down by both parents, though only daughters get it from their father as the father sends over the Y Chromosome to their son instead. This makes for a weird line of inheritance through your ancestry. A good way to figure this out is to use a fan chart. I was able to find a chart on this helpful post over at The Genetic Genealogist about the X Chromosome. Here is my chart, filled in with my ancestors, telling me where I could have inherited my X Chromosome:
The charts can be found over at The Genetic Genealogist, though I had to increase the image size a bit to make it easier to work with. There is also a chart showing the estimated percentage of the X Chromosome that you get from each ancestor.
I obviously don’t have all of the boxes filled in as I don’t have those ancestors figured out, yet. On my research over at GEDMatch, I see that I match a few people on my X Chromosome. So, in theory, these people would be related to me through those ancestors in the chart above (or beyond, in the same sequence.) My French-Canadian ancestry is included in the chart above, so I undoubtedly will have a lot of connections through there as I always do. It’s not a silver bullet by any means, but it does help you narrow down your search if you find a connection, especially along with other matches in other DNA areas or common surnames.
Again, there is another very quick and helpful video on the X Chromosome over at the University of Utah’s Molecular Genealogy page. I would definitely watch it.
Next time we will talk about the other 22 Chromosomes or the Autosomal DNA.