Tabaccus Maximus
Tabaccus Maximus
- Messages
- 169
- Reaction score
- 22
- Points
- 0
- Ethnic group
- Galo-Germanic Atlantic Fringe
- Y-DNA haplogroup
- R1b - SRY 2627
- mtDNA haplogroup
- H1a
Lactase Persistence (ability to digest raw milk comfortably) appears suddenly in Europe after the late neolithic where it was virtually absent before. In Northwestern Europe today it reaches into the ninetieth percentile and in some areas is almost uniformly present. It then forms a cline that slowly descends throughout Northwest Eurasia down to zero.
One theory suggested present levels of LP in Europe came about due to the cloudy environment in which Vitamin D and Calcium may have enriched the lives of the natives and was thereby was very positively selected to its present frequency. "the calcium assimilation hypothesis"
Dienekes has posted a link to a study that examines this theory in detail which finds it lacking. (Sverrisdottir et al, 2014) http://dienekes.blogspot.com/2014/01/lactase-persistence-and-natural.html
I thought Dienekes made an interesting point on LP selection vs. LP admixture:
I think what this suggests is:
1) LP is most likely not native to Europe
2) LP was brought to Europe involving a substantial population replacement by individuals already LP
3) Beneficial traits may not always be the subject of strong positive selection, otherwise we would all be tall and beautiful.
It's worth noting that the world's largest populations in Asia, S. Asia and Indo-China are nearly completely Lactose Intolerant, yet LP has probably been introduced multiple times over the millenia.
One theory suggested present levels of LP in Europe came about due to the cloudy environment in which Vitamin D and Calcium may have enriched the lives of the natives and was thereby was very positively selected to its present frequency. "the calcium assimilation hypothesis"
Dienekes has posted a link to a study that examines this theory in detail which finds it lacking. (Sverrisdottir et al, 2014) http://dienekes.blogspot.com/2014/01/lactase-persistence-and-natural.html
I thought Dienekes made an interesting point on LP selection vs. LP admixture:
For example, the lactase persistence allele occurs at a non-trivial frequency in present-day inhabitants of the Americas, whereas it was zero there a few thousand years ago, with the culprit being post-1492 European colonization. The frequency change in the Americas didn't happen because of natural selection, but because a new population (Europeans) moved in.
I think what this suggests is:
1) LP is most likely not native to Europe
2) LP was brought to Europe involving a substantial population replacement by individuals already LP
3) Beneficial traits may not always be the subject of strong positive selection, otherwise we would all be tall and beautiful.
It's worth noting that the world's largest populations in Asia, S. Asia and Indo-China are nearly completely Lactose Intolerant, yet LP has probably been introduced multiple times over the millenia.