Lack of Lactose Intolerace Genes May Show Hunter-Gatherer Population Replaced in Scandinavia

An article by a group of geneticists called ”High frequency of lactose intolerance in a prehistoric hunter-gatherer population in northern Europe” has shown that the allele connected with lactose-sugar consumption in adults was not at as high of a frequency in Hunter-Gatherer DNA that they tested(Malmström et al. 2010). The article by Helena Malmström, Anna Linderholm, Kerstin Lidén, Jan Storå, Petra Molnar, Gunilla Holmlund, Mattias Jakobsson and Anders Götherström, shows a marked contrast between the people who lived in the Scandinavia area 5,400-4,300 BP and the people who live there now.

The Hunter-Gatherer group that Malmström et al. looked at a group of Pitted Ware Culture people trying to see if there was any testable remains. As it turned out there were ten PWC remains that were testable for the -13910*T allele. However the results were not what they expected with only 5% testing for having the -13910*T/lactose-sugar tolerance gene. This is particularly surprising because Scandinavia currently holds the highest population of lactose-tolerant people at 74%. So the conclusion of Malmström et al is that either there was a selective breeding process for the lactose-tolerant genes, or (and this is what they actually belive happened) the PWC population was replaced by another population that already had a high frequency of the -13910*T allele in their group.

This is a great article because while it could have gotten bogged down by scientific talk, the authors made a marked effort to make it clear to any reader exactly what they were talking about. Even people with very little knowledge of genetics should be able to pick this up and understand that due to the Malmström et al’s data most likely the PWC population was replaced by another population who could tolerate lactose-sugar. When discussing how to do public archaeology, this is an article that can be shown as an example.

With that said though, there are some problems. Considering that the PWC culture was a large population for its time, and would probably be considered a complex hunter-gatherer group only getting ten samples should not be enough to draw too many conclusions. It is odd to only see 5% even out of ten samples of lactose tolerance in Scandinavia, however ten samples is not amazingly conclusive. To really draw the conclusions that Malmström et al make about the PWC population being replaced by a group of sedentary agriculturalists there needs to be a secondary DNA analysis done for the -13910*T allele in a different group of PWC remains.

Malmström H, A Linderholm, K Lidén, J Storå, P Molnar, G Holmlund, M Jakobsson, and A Götherström
2010 "High frequency of lactose intolerance in a prehistoric hunter-gatherer population in northern Europe". BMC Evolutionary Biology. 10.