Horses aren't on there so maybe the artist didn't realize that they are a MAJOR source of milk in any horse culture. I can purchase mare's milk cheese in over a dozen stores in this community.
Recent in depth studies regarding the modern spread of lactose tolerance among the Sa'ami indicate that it's not exactly the auto-somal recessive it was formerly believed to be.
A single allele is enough to confer the beneficial effect on a person provided the local environment has milk available. That increases the rate of spread to near lightspeed ~ half a dozen generations and EVERYBODY's got it.
Horses aren’t on there so maybe the artist didn’t realize that they are a MAJOR source of milk in any horse culture. I can purchase mare’s milk cheese in over a dozen stores in this community.
They also talk about “Asians” not having the gene to digest milk. This is true of most south Asians, but most north Asians have lived on the stuff for millenia. Mongols and all that.
Indiana?
So what would the low levels of lactose tolerance in north africa and the middle east mean?