Domestication interests us as the most momentous change in Holocene human history. Why did it operate on so few wild species, in so few geographic areas? Why did people adopt it at all, why did they adopt it when they did, and how did it spread? The answers to these questions determined the remaking of the modern world, as farmers spread at the expense of hunter-gatherers and of other farmers.

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Evolution, consequences and future of plant and animal domestication

▪ Abstract About 20 years ago, DNA sequences were separately described from the quagga (a type of zebra) and an ancient Egyptian individual. What made these DNA sequences exceptional was that they were derived from 140- and 2400-year-old specimens. However, ancient DNA research, defined broadly as the retrieval of DNA sequences from museum specimens, archaeological finds, fossil remains, and other unusual sources of DNA, only really became feasible with the advent of techniques for the enzymatic amplification of specific DNA sequences. Today, reports of analyses of specimens hundreds, thousands, and even millions of years old are almost commonplace. But can all these results be believed? In this paper, we critically assess the state of ancient DNA research. In particular, we discuss the precautions and criteria necessary to ascertain to the greatest extent possible that results represent authentic ancient DNA sequences. We also highlight some significant results and areas of promising future research.

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Genetic Analyses from Ancient DNA

Mitochondrial DNA (mtDNA) sequences from 686 wild and domestic pig specimens place the origin of wild boar in island Southeast Asia (ISEA), where they dispersed across Eurasia. Previous morphological and genetic evidence suggested pig domestication took place in a limited number of locations (principally the Near East and Far East). In contrast, new genetic data reveal multiple centers of domestication across Eurasia and that European, rather than Near Eastern, wild boar are the principal source of modern European domestic pigs.

https://science.sciencemag.org/content/sci/307/5715/1618.full.pdf

Worldwide Phylogeography of Wild Boar Reveals Multiple Centers of Pig Domestication

The widespread extinctions of large mammals at the end of the Pleistocene epoch have often been attributed to the depredations of humans; here we present genetic evidence that questions this assumption. We used ancient DNA and Bayesian techniques to reconstruct a detailed genetic history of bison throughout the late Pleistocene and Holocene epochs. Our analyses depict a large diverse population living throughout Beringia until around 37,000 years before the present, when the population's genetic diversity began to decline dramatically. The timing of this decline correlates with environmental changes associated with the onset of the last glacial cycle, whereas archaeological evidence does not support the presence of large populations of humans in Eastern Beringia until more than 15,000 years later.

/pdf/rise-and-fall-of-the-beringian-steppe-bison-4le6feu22j.pdf

Rise and Fall of the Beringian Steppe Bison

Lactase persistence (LP) is common among people of European ancestry, but with the exception of some African, Middle Eastern and southern Asian groups, is rare or absent elsewhere in the world. Lactase gene haplotype conservation around a polymorphism strongly associated with LP in Europeans (213,910 C/T) indicates that the derived allele is recent in origin and has been subject to strong positive selection. Furthermore, ancient DNA work has shown that the 213,910*T (derived) allele was very rare or absent in early Neolithic central Europeans. It is unlikely that LP would provide a selective advantage without a supply of fresh milk, and this has lead to a gene-culture coevolutionary model where lactase persistence is only favoured in cultures practicing dairying, and dairying is more favoured in lactase persistent populations. We have developed a flexible demic computer simulation model to explore the spread of lactase persistence, dairying, other subsistence practices and unlinked genetic markers in Europe and western Asia’s geographic space. Using data on 213,910*T allele frequency and farming arrival dates across Europe, and approximate Bayesian computation to estimate parameters of interest, we infer that the 213,910*T allele first underwent selection among dairying farmers around 7,500 years ago in a region between the central Balkans and central Europe, possibly in association with the dissemination of the Neolithic Linearbandkeramik culture over Central Europe. Furthermore, our results suggest that natural selection favouring a lactase persistence allele was not higher in northern latitudes through an increased requirement for dietary vitamin D. Our results provide a coherent and spatially explicit picture of the coevolution of lactase persistence and dairying in Europe.

/pdf/the-origins-of-lactase-persistence-in-europe-553ptfhim5.pdf

The Origins of Lactase Persistence in Europe

The limited ranges of the wild progenitors of many of the primary European domestic species point to their origins further east in Anatolia or the fertile crescent. The wild ox (Bos primigenius), however, ranged widely and it is unknown whether it was domesticated within Europe as one feature of a local contribution to the farming economy. Here we examine mitochondrial DNA control-region sequence variation from 392 extant animals sampled from Europe, Africa and the Near East, and compare this with data from four extinct British wild oxen. The ancient sequences cluster tightly in a phylogenetic analysis and are clearly distinct from modern cattle. Network analysis of modern Bos taurus identifies four star-like clusters of haplotypes, with intra-cluster diversities that approximate to that expected from the time depth of domestic history. Notably, one of these clusters predominates in Europe and is one of three encountered at substantial frequency in the Near East. In contrast, African diversity is almost exclusively composed of a separate haplogroup, which is encountered only rarely elsewhere. These data provide strong support for a derived Near-Eastern origin for European cattle.

Christopher S. Troy

Papers

Genetic evidence for Near-Eastern origins of European cattle