The lactase-persistence-associated allele in early Neolithic Europeans

The lactase-persistence-associated allele in early Neolithic Europeans

Lactase persistence (LP), the dominant Mendelian trait conferring the ability to digest the milk sugar lactose in adults, has risen to high frequency in central and northern Europeans in the last 20,000 years. This trait is likely to have conferred a selective advantage in individuals who consume appreciable amounts of unfermented milk. Some have argued for the “culture-historical hypothesis,” whereby LP alleles were rare until the advent of dairying early in the Neolithic but then rose rapidly in frequency under natural selection. Others favor the “reverse cause hypothesis,” whereby dairying was adopted in populations with preadaptive high LP allele frequencies. Analysis based on the conservation of lactase gene haplotypes indicates a recent origin and high selection coefficients for LP, although it has not been possible to say whether early Neolithic European populations were lactase persistent at appreciable frequencies. We developed a stepwise strategy for obtaining reliable nuclear ancient DNA from ancient skeletons, based on (i) the selection of skeletons from archaeological sites that showed excellent biomolecular preservation, (ii) obtaining highly reproducible human mitochondrial DNA sequences, and (iii) reliable short tandem repeat (STR) genotypes from the same specimens. By applying this experimental strategy, we have obtained high-confidence LP-associated genotypes from eight Neolithic and one Mesolithic human remains, using a range of strict criteria for ancient DNA work. We did not observe the allele most commonly associated with LP in Europeans, thus providing evidence for the culture-historical hypothesis, and indicating that LP was rare in early European farmers.

Just an archived item- I’ve posted a news  item on this before but it’s nice to have the paper. The lactose tolerance seems to only about 8,000 years old, and has occured independantly in several different pastoralist groups around the world. I guess retention of a juvenille trait is an easy mutation for the genome to make. Last time I looked it was worked out on a computer simulation to have spread with the  Linearbandkeramik culture

3 responses to “The lactase-persistence-associated allele in early Neolithic Europeans

  1. “I guess retention of a juvenille trait is an easy mutation for the genome to make. ”

    In this case it seems different alleles are able to yeald the same phenotypical trait. That allowed evolutionary convergence by different groups in different times. In other words, the mutation that allowed lactore tolerance in sub-Saharan populations was not the same that happened in central Asia. Really cool.

  2. I guess retention of a juvenille trait is an easy mutation for the genome to make.

    I agree.

    Last time I looked it was worked out on a computer simulation to have spread with the Linearbandkeramik culture

    Might be. Still the highest concentrations of the alelle are north and west of the Danubian area, in Scandinavia and Britain, as well as in the Basque Country (check Enattah 2007. These Atlantic peoples have higher lactose tolerance levels than Central Europeans (founder effect? cultural selection for being more intesely pastoralist?)

    Anyhow, I’d suggest studying aDNA of Magdalenians as they might have domesticted the horse early on.

    • Anyhow, I’d suggest studying aDNA of Magdalenians as they might have domesticted the horse early on

      Yes; I’ve seen that on your blog. I think catching wild ones and using them like native Americans did rather than domestication proper is about all you’d see that far back though, not proper domestication.

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