Genetic isolates

I recently used  one of those services where you send a saliva sample to a lab somewhere for DNA analysis. A part of the study just came back, telling me that I am 99.5% Ashkenazi Jewish, with perhaps a solitary Egyptian (!) ancestor 5 to 8 generations back. (Some tell me, however, that such very low % estimates are not very reliable.)

Mentioning this to friends on Facebook, I found that a whole lot of Jewish people in my age range who grew up in the US Northeast also did tests of this kind, and likewise were repeatedly found to be 98% or more Ashkenazi Jewish.

This suggests a truly striking degree of genetic isolation over many centuries, which of course is now perhaps trending way downwards. It pertains not just to marriage but also to anything else that might have led to children who had children. Given the centuries-long oppression of European Jews, one might have expected more forcible violations of Jews' genetic isolation. But perhaps any such children didn't fare as well for social / cultural reasons.

I also gather that all living Ashkenazi Jews are thought to be the survivors of a population bottleneck, descended from just a few hundred people (at most) who lived in late medieval times. (Were all the other European Jews from the diaspora murdered?) But there is controversy about their Middle Eastern as opposed to European ancestry, with possible gender differences. (Y chromosomes, obviously, pass only through the male line, while mitochondrial DNA passes only through the female line.)

Still waiting for the report on my degree of Neanderthal ancestry. You know the old joke (actually, I think it's mine): "Why am I 98% genetically the same as a chimp, but only 50% the same as my parents, siblings, and children?"

Fun with COVID statistics

 Two apparent facts about COVID-related statistics that I've read about in the last few days.

1) Average wages apparently rose in 2020, due to COVID - but the main reason was that lower wage earners disproportionately lost their jobs. So, with them taken disproportionately out of the workforce, those who still had jobs had higher average wages - wholly without regard to any wage gains from jobs that survived.

2) In the next ten years, it's apparently expected that the surviving American population will be on average healthier, and have longer average expected lifespans, than if COVID hadn't happened. But the reason is that older people who were less healthy than the average, and yet had life expectancies of, say, 5 to 10 years, were disproportionately killed now.

This makes the great human loss from these people's losing years that they otherwise would have had look as if it were actually a gain. After all, if the population were the same and life expectancies increased, that would clearly be good. But just as people's economic welfare declines if they lose their low-wage jobs - but this misleadingly causes average wages to increase - thus prematurely killing off the less-healthy makes it misleadingly seem as if constant-population lives were lengthening.

Mark Twain's famous (and if anything over-familiar) line about "lies, damned lies, and statistics" draws mainly, at least as I have always interpreted it, on the opportunities those citing statistics may have to choose the deliberately misleading. No doubt that will go on here as well. But it's also the case that we can in good faith mislead ourselves with (in these two cases) average figures drawn from a sub-group consisting of the more fortunate, when what we actually (do or should) care about is the larger group, including the less fortunate.