@Owl @Zerglingman @mimorinka “Hybrid vigor is bullshit”
It’s a simplification of something that works for things like corn, when you start from a couple of inbred AKA purebred varieties, and experience tells us getting two alleles for a number of genes makes a much better plant for the resulting generation.
See https://en.wikipedia.org/wiki/Heterosis Ignore the “Major histocompatibility complex in animals” [citation needed], pretty sure we’ve known since the 1970s or earlier that’s not how it works. On the other hand the Flynn effect discussion at the end sounds legit.
There’s extremes of human inbreeding that are obviously bad, see Arabs etc. and other races that practice cousin marriage and their birth defect rates for example. And you’d expect early humans to have suffered from the same sorts of things depending on how much out-breeding happened from war or culture or whatever. We also went through a very narrow genetic window when something reduced our total numbers to, what, ~40K?
One of the most interesting things about Ashkenazi Jews was their ability to pull off a human eugenic program that is at net successful, but does have the characteristic higher rate of birth defects as well as the physiognomy that makes it so easy to detect a lot of them (and to the extent that makes them objectively ugly on an absolute scale it also supports the program; see tribes/ethnic groups that mutilate their children’s appearance around/before puberty). IQs well below 100 suggest Mizrahi and Sephardi Jews failed.
But back to the thesis, if you don’t start with purebred humans which we obviously haven’t created (it would take centuries for one thing) then it’s rolling a great many dice with seriously different outcomes. For example, I look very much like one parent, my siblings while not as close look like the other parent, like in overt things like eye colors. And we all got bad allergies from one parent which isn’t at all good. But my IQ is absolutely the result of “hybrid vigor” which maybe one sibling shares to a moderate degree.
But that’s from Northeastern European parents, and in the common US pattern also resulted in a major jaw/tooth size mismatch for myself, requiring orthodontics including the removal of one set of semi-molars to make room for the rest minus the wisdom teeth later.
When we get to wildly different human races like the three big ones, the possibilities have got to really explode; also see how dominate negro genes are in mulattoes like Obama, fully white mother, fully African father. I wonder if anyone has any good data on the details of this, since it violates the (((blank slate fallacy))) and so many other Jewish intellectual movements and programs (as usual, see https://www.unz.com/book/kevin_macdonald__the-culture-of-critique/ for how those work, as or like cults vs. SCIENCE!!!).
But we do know of plenty of specific examples where it just doesn’t work well at net, and at an extreme example of two species, see mules, an infertile donkey/cross that (when successful???) has advantages as a work animal. Which of course is how Jews view us.