I cannot remember where I got this map from, but the light areas show outbreeding and the darkest ones show the most inbreeding.
I find it very interesting because of this map:
This map is from Charles Murray's Human Accomplishment, in which he found 98% of all the discoveries in the world came from Europe and its descendents in the rest of the world. When I saw the top map the lower map immediately sprang to mind.
Even more interesting, Murray found that those accomplishments were concentrated in certain areas of Europe. If you compare those two maps, you'll see some intriguing things.
Where there was the most outbreeding there was the most accomplishment. Look specifically at northern Italy, England, and central Europe.
I find this astonishing.
It didn't occur to me until recently that in those days most people couldn't travel that much. I recently got on a plane and flew over 1000 miles in about four hours. In the past, you couldn't travel any faster than the fastest horse.
None of this, of course, means indiscriminate outbreeding. Sub-Saharan Africa, for example, has produced nothing of any value. India, Asia, South America and the Middle East put together contributed only contributed about two percent.
I've read several times that about 50% of what we are is inherited. The rest is environmental. If this is true (and I think it is) then we should be very careful about whom we have children with.