Low Prevalence of Lactase Persistence in Bronze Age Europe Indicates Ongoing Strong Selection over the Last 3,000 Years

• Published in: Current biology Vol. 30; no. 21; pp. 4307 - 4315.e13
• Main Authors: Burger, Joachim, Link, Vivian, Blöcher, Jens, Schulz, Anna, Sell, Christian, Pochon, Zoé, Diekmann, Yoan, Žegarac, Aleksandra, Hofmanová, Zuzana, Winkelbach, Laura, Reyna-Blanco, Carlos S., Bieker, Vanessa, Orschiedt, Jörg, Brinker, Ute, Scheu, Amelie, Leuenberger, Christoph, Bertino, Thomas S., Bollongino, Ruth, Lidke, Gundula, Stefanović, Sofija, Jantzen, Detlef, Kaiser, Elke, Terberger, Thomas, Thomas, Mark G., Veeramah, Krishna R., Wegmann, Daniel
• Format: Journal Article
• Language: English
• Published: England Elsevier Inc 02-11-2020
• Subjects: Bronze Age battlefield; human population genetics; lactase; selection; Bronze Age battlefield; human population genetics; selection; lactase
• ISSN: 0960-9822; 1879-0445
• DOI: 10.1016/j.cub.2020.08.033

Lactase persistence (LP), the continued expression of lactase into adulthood, is the most strongly selected single gene trait over the last 10,000 years in multiple human populations. It has been posited that the primary allele causing LP among Eurasians, rs4988235-A [1], only rose to appreciable frequencies during the Bronze and Iron Ages [2, 3], long after humans started consuming milk from domesticated animals. This rapid rise has been attributed to an influx of people from the Pontic-Caspian steppe that began around 5,000 years ago [4, 5]. We investigate the spatiotemporal spread of LP through an analysis of 14 warriors from the Tollense Bronze Age battlefield in northern Germany (∼3,200 before present, BP), the oldest large-scale conflict site north of the Alps. Genetic data indicate that these individuals represent a single unstructured Central/Northern European population. We complemented these data with genotypes of 18 individuals from the Bronze Age site Mokrin in Serbia (∼4,100 to ∼3,700 BP) and 37 individuals from Eastern Europe and the Pontic-Caspian Steppe region, predating both Bronze Age sites (∼5,980 to ∼3,980 BP). We infer low LP in all three regions, i.e., in northern Germany and South-eastern and Eastern Europe, suggesting that the surge of rs4988235 in Central and Northern Europe was unlikely caused by Steppe expansions. We estimate a selection coefficient of 0.06 and conclude that the selection was ongoing in various parts of Europe over the last 3,000 years.
•Genomic data from Tollense, the oldest large-scale conflict site north of the Alps•Novel method indicates that Bronze Age warriors represent an unstructured population•Lactase persistence frequency in Tollense (7.1%) is significantly lower than today•Selection coefficient estimate of 6% over the last 3,000 years
Burger et al. report the first genomic data from the oldest known battlefield north of the Alps. With additional data from 55 individuals from sites in Southern and Eastern Europe dating to the Bronze Age, they find evidence for a strong and ongoing selection on lactase persistence in various parts of Europe over the last 3,000 years.