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Prejudice may be the best way to determine genetic history March 9, 2009

Posted by ethnicgenome in Genetics (General).
Tags: , , ,

I have a strong feeling that people knowing your ethnicity’s haplogroups will tell you more than your own. Y-DNA and mtDNA are a very small part of one’s genetic history. Your mother’s father and all his ancestors, and of your father’s mother and all her ancestors can’t be seen. Same with your maternal grandmother’s father and with your paternal grandfather’s mother. And so on, so forth.

But for a nation, we have too big a sample. If 20% of a given ethnic group are in haplogroup K, my guess would be that roughly roughly 20% of the genes of all the people in that ethnic group are K. So although your DNA test may show that you may be haplogroup K and your neighbor is haplogroup H, the reality is that you both likely have a similar background.

This is just a guess of course, but I am fairly certain about it considering how much mixing there has been among people of the same nation over thousands of years.

The other reason I think so is that people of the same nation look mostly somewhat similar. Not identical of course, but usually similar enough that they can say things like, “this guy looks Swedish and this guy looks Italian.”

Again people may not necessarily look like their their own ethnicity (an Italian may have a Swedish great grandfather whom he never met, but whom he resembles), but there’s a particular “look” to most ethnicities. The closer they are, the harder it is to tell. Thus the Poles and the Russians may be difficult to tell apart sometimes (except usually by the Russians and the Poles themselves), but it is much easier to tell the Poles from the Greeks (again not always, but usually).

The fact that there’s an “Irish look” or a “Dutch look” leads me to believe that most people within a particular ethnicity same a similar amount of each haplogroup. Otherwise, they would look much more different.

There are of course countries where people seem to have different amounts of their haplogroups. Italy, Israel, Turkey, Russia, Finland would be a few examples. But now you can see a difference between people in these cases (north Italy and Finland vs. South; Eastern Russia vs. Western; Sephardic vs. Ashkenazi Jews).

Even though both Sephardic and Askhenazi Jews descended from the same haplogroups (mtDNA and Y-DNA), they have a different mix and therefore look different.

I would therefore guess that it is not that 19% of the Ashkenazim are J1 (usually Arabs), 23% are J2 (usually Mediterranean Europeans), 13% R1a (Slavs, Aryans), 11.5% are R1b (Western Europe), etc. Instead, the Ashkenazim all have Y-DNA somewhere around these percentages.

Likewise, I believe that the people native to northern parts of Finland and eastern parts of Russia (beyond Ural) are probably mostly of Asian descent, genetically linked to some Amerindian tribes. It’s not that 60% of the people there are part of haplogroup N (Y-DNA), but rather almost all the people there are 40-80% N.

Some may have more of a given haplogroup and some may have less, but I would bet that estimating by using “prejudice” based on a person’s ethnicity is more accurate, if not completely exact, than testing one’s mtDNA and Y-DNA, and leaving out all other ancestry.