>>/6648/

Here's an example of relevant calculation.
https://www.reddit.com/r/slatestarcodex/comments/4t8tgl/question_about_the_ashkenazi_iq_hypothesis/d5ktie6/

>  Could you estimate the effects on GDP and HDI
I could estimate the decline in human capital to somewhere between current US and current Mexico. 

>  and should we really worry given the likely progress in embryo selection and brain upgrading tech? 
Absolutely; reliance on non-existent and possibly politically untenable science woo that depends on current rate of progress is irresponsible. I do hope for these developments myself, though.

>  I assume that the high-IQ groups (coastal whites, Jews, Asians) pair bond mostly within these groups
Indeed, they bond mostly within these groups with sub-replacement fertility. Also, I'm vehemently against complete replacement of high-IQ Whites with psychopathic half-breeds who will rant about their bar mitzvah, superiority of mixed race marriage, moral necessity of abortion and how the future is poly.