We got email from 23andme yesterday that more of our DNA data was ready. You may remember that last time I talked about the maternal & paternal haplogroups. These are the two lines which you can track directly into the deep past. Your maternal haplogroup is a group formed by the pattern of SNPs on your mitochondrial DNA. Because the sperm’s mitochondria are discarded during fertilization, all of your mitochondrial DNA comes from your mother, and from her mother, and from her mother, …
We already knew from the earlier data that Chris and the kids belonged to the maternal haplogroup U5a1b1. Now we know that I belong to the maternal haplogroup H16. 23andme’s website has this neat little zoomable viewer you can use to see how the different haplogroups are related to each other.
The maternal and paternal haplogroups give you two vectors which go deep into your ancestry. If you look at this very simplified diagram of our family,
you can see the U5a1b1 maternal haplogroup coming in from Chris’ mother’s mother’s … mother back for many, many generations. In the same way, the R1b1b2a1a2f2 paternal haplogroup comes in from my father’s father’s …. father from many generations back. Notice that we can’t see Chris’ father’s paternal haplogroup on this diagram. Because Chris doesn’t have a Y chromosome, we’d need to test Chris’ father to find that information.
Outside of your mitochondria and Y chromosome, things get a lot more complicated because of crossover. For each of your homologous pairs, you got one from your father and one from your mother, but crossover means that each of those is made up of a mixture of genes from their mother and father. You can do some statistical analysis of ancestry on this DNA, but you don’t get anything as clear as these two bright lines heading off into the distant past.