Well, race is a very ill defined term from a genetic point of view. How would you define “white”? “Black” covers vastly more, genetically speaking, than all the other races put together. Which is to be expected, since humans originated in Africa. Where your ancestors are from is important in that it will make you more or less susceptible to various things (e.g. Africans are more resistant to malaria, Scandinavians are more resistant to HIV, pastoral people can tolerate lactose), but these tend to be single genes, or at most a few. In the case of features that are regulated by multiple genes, it’s spread out a lot more, with lots of genes giving small boosts.
In the case of intelligence, it’s a bit like asking whether there’s a homosexuality or speech gene. The simple answer is no, the deeper answer is (as always in biology) “it depends”. For example, in the case of speech, there is a family in England that has a genetic disorder that results in them not being able to speak. This doesn’t mean that FOXP2 is responsible for speech. It just means that it’s a critical element, the lack of which will break the speech system.
Intelligence is (most likely) similar. There are lots (hundreds or thousands) of genes correlated with intelligence. These genes are spread all over the gene pool, which has always (except remote islands, e.g. Tasmania) been mixing itself around. If there was a single gene for intelligence, I’m pretty sure it would spread really fast, unless it was a recent (e.g. 1000 years) mutation. Unless it was somehow intrinsically connected to superficial characteristics like toenail size, beard length, or skull shape, the intelligence gene would spread to other places without changing how the recipients look.
It’s like eyesight. Having good eyes is very useful. So you’d expect most people to have similar levels of sight (sans various defects and with a normalish distribution) because natural selection will be pushing up to the Pareto limit. Intelligence is similar. It’s too useful to give up.
An interesting example of cultural differences being more explanatory than genetics are the Dutch. Before 1875, the median height of Dutch men was 165cm. In 2014 it was 174cm. That’s not something that can be explained well with genetics (it’s too fast). The most likely explanation is that their genes had the potential to be really tall, but the environment didn’t supply enough resources. Average height is actually one of the best measures of social well being (along with when girls start menstruating), as it’s very sensitive to how healthy children are (each skipped meal and each illness result in a little less growth).
Well, race is a very ill defined term from a genetic point of view. How would you define “white”? “Black” covers vastly more, genetically speaking, than all the other races put together. Which is to be expected, since humans originated in Africa. Where your ancestors are from is important in that it will make you more or less susceptible to various things (e.g. Africans are more resistant to malaria, Scandinavians are more resistant to HIV, pastoral people can tolerate lactose), but these tend to be single genes, or at most a few. In the case of features that are regulated by multiple genes, it’s spread out a lot more, with lots of genes giving small boosts.
In the case of intelligence, it’s a bit like asking whether there’s a homosexuality or speech gene. The simple answer is no, the deeper answer is (as always in biology) “it depends”. For example, in the case of speech, there is a family in England that has a genetic disorder that results in them not being able to speak. This doesn’t mean that FOXP2 is responsible for speech. It just means that it’s a critical element, the lack of which will break the speech system.
Intelligence is (most likely) similar. There are lots (hundreds or thousands) of genes correlated with intelligence. These genes are spread all over the gene pool, which has always (except remote islands, e.g. Tasmania) been mixing itself around. If there was a single gene for intelligence, I’m pretty sure it would spread really fast, unless it was a recent (e.g. 1000 years) mutation. Unless it was somehow intrinsically connected to superficial characteristics like toenail size, beard length, or skull shape, the intelligence gene would spread to other places without changing how the recipients look.
It’s like eyesight. Having good eyes is very useful. So you’d expect most people to have similar levels of sight (sans various defects and with a normalish distribution) because natural selection will be pushing up to the Pareto limit. Intelligence is similar. It’s too useful to give up.
An interesting example of cultural differences being more explanatory than genetics are the Dutch. Before 1875, the median height of Dutch men was 165cm. In 2014 it was 174cm. That’s not something that can be explained well with genetics (it’s too fast). The most likely explanation is that their genes had the potential to be really tall, but the environment didn’t supply enough resources. Average height is actually one of the best measures of social well being (along with when girls start menstruating), as it’s very sensitive to how healthy children are (each skipped meal and each illness result in a little less growth).