I thought the Vox article explained the issues involved pretty well.
As I understand it (and I'm not that knowledgeable either), people who are more closely related (from a genetic point of view) are likely to have more similar intelligence. However, that's pretty much all you can say. How closely related you are doesn't map to anything else cleanly.
It seems like that's pretty much what you'd expect from a lot of genes that contribute a tiny effect and are nearly randomly passed on to descendants.
> people who are more closely related (from a genetic point of view) are likely to have more similar intelligence.
This may seem almost trivial, as most people probably have this opinion anyway. But it still has inconvenient ramifications for egalitarism. For example: is someone in Harvard because their filthy rich family bought them a place and had connections ... or are they maybe clever because they come from a clever family?
> How closely related you are doesn't map to anything else cleanly.
People who are more related tend to be of similar height. Also, people who are related tend to have similar IQ. But that doesn't mean height correlates with IQ because they're not necessarily the same genes.
The hot potatoe is of course "race" (what US-Americans equate for some reason with skin color), or more specifically shared-ancestry-ethnicity (northern european vs southern europeans vs slavs vs ashkenazi jews vs sephardi jews vs south eastern asians vs east asians … etc)
As I understand it (and I'm not that knowledgeable either), people who are more closely related (from a genetic point of view) are likely to have more similar intelligence. However, that's pretty much all you can say. How closely related you are doesn't map to anything else cleanly.
It seems like that's pretty much what you'd expect from a lot of genes that contribute a tiny effect and are nearly randomly passed on to descendants.