Human Genetics

[Moontanman]

A profound video everyone should watch.

 

 

[Fluxus]

Yeah, I dunno. This doesn't sound meaningful at all to me.

 

For example, populations were isolated from each other for tens of thousands of years. The earliest suggested time for the Americas being populated was around 15,000 years ago; some believe it may have been as long as 40,000 years ago. In the year 1500 CE, Montezuma was in Mexico and descended from a population that, as far as we know, had no contact with Europeans. Using the narrator's model, Montezuma and Solon of Athens "must" have had a common ancestor at some point, but it is physically impossible for Montezuma to be descended from Solon. You'd have to go back well over 15,000 years to find a common ancestor for the two.

 

Placing the MRCE at a fairly early date is due to the European conquest of those regions, which is relatively recent. As a result, the European contribution to the DNA of someone born today in Mexico will depend greatly on their descendants. For some that will be a significant amount, for others negligible.

 

Further, genes don't necessarily survive all those generations. You have a finite number of genes, and due to meiosis you basically get half the genes from each parent. Thus, each generation you go back, in theory the genetic data is cut in half -- e.g. 50% from your parents, 25% from your grandparents. In 10 generations you're receiving 0.048828125% of that ancestor's genetic lineage; in 20 generations, 0.00004768371582%.... If we follow the same line of thought as the narrator here, it's only a few generations before each ancestor contributes less than 1 gene to your total makeup, which is absurd.

 

If anything, such an analysis seems to indicate a lesser importance of ancestry is in a biological sense, since selecting a paternal or maternal lineage is essentially an arbitrary pathway through what quickly becomes a large family tree. The further back you go, the less influence any one individual has on your genetic makeup.

 

In other words, the way that I am related to Julius Caesar -- or one of his slaves -- is so minuscule, and has so little biological influence on me, that at least on a personal level it is effectively meaningless.

 

I'd say that more general descriptions of population migrations, while far less personal, yields more meaningful information.