Dual Origins of Dairy Cattle Farming – Evidence from a Comprehensive Survey of European Y-Chromosomal Variation

Abstract

BackgroundDiversity patterns of livestock species are informative to the history of agriculture and indicate uniqueness of breeds as relevant for conservation. So far, most studies on cattle have focused on mitochondrial and autosomal DNA variation. Previous studies of Y-chromosomal variation, with limited breed panels, identified two Bos taurus (taurine) haplogroups (Y1 and Y2; both composed of several haplotypes) and one Bos indicus (indicine/zebu) haplogroup (Y3), as well as a strong phylogeographic structuring of paternal lineages.Methodology and Principal FindingsHaplogroup data were collected for 2087 animals from 138 breeds. For 111 breeds, these were resolved further by genotyping microsatellites INRA189 (10 alleles) and BM861 (2 alleles). European cattle carry exclusively taurine haplotypes, with the zebu Y-chromosomes having appreciable frequencies in Southwest Asian populations. Y1 is predominant in northern and north-western Europe, but is also observed in several Iberian breeds, as well as in Southwest Asia. A single Y1 haplotype is predominant in north-central Europe and a single Y2 haplotype in central Europe. In contrast, we found both Y1 and Y2 haplotypes in Britain, the Nordic region and Russia, with the highest Y-chromosomal diversity seen in the Iberian Peninsula.ConclusionsWe propose that the homogeneous Y1 and Y2 regions reflect founder effects associated with the development and expansion of two groups of dairy cattle, the pied or red breeds from the North Sea and Baltic coasts and the spotted, yellow or brown breeds from Switzerland, respectively. The present Y1-Y2 contrast in central Europe coincides with historic, linguistic, religious and cultural boundaries.

On the Breeds of Cattle—Historic and Current Classifications

“…This has been explained by repopulation of South France after the Gallic conquest or during the Middle Ages by Alpine cattle [55], but is not consistent with the proposed different migration routes for Alpine and South-French cattle, respectively [83].…”

“…Biochemical clustering was the start of a new scientific approach and also generally followed a mainly geographic division. Classifying on the basis of geography is supported by molecular analysis which shows that geographical origin is the most important determinant of breed relationships [12,54,55,97] This is of fundamental interest and is also justified by the notion that most breed names refer to geographical origin.…”

“…Particularly the Lowland black-pied, Ayrshires and Central Brown now occur in European regions far from their region of origin. However, the contrast of Northern cattle, predominantly carrying the Y1-type Y-chromosomes, and the central and southern European cattle, mainly carrying Y2 Y-chromosomes, has been retained and has apparently an old origin [55].…”

“…A collective effort of several European laboratories supported by the European Commission led to a compilation of a microsatellite data set of all major and several local cattle breeds (Table S34) [54,55,94,95]. Analysis of the data with phylogenetic networks ( Figure S2) in combination with model-based clustering [96] Table S35).…”

Interrogation of modern and ancient genomes reveals the complex domestic history of cattle

“…On the other hand, nuclear DNA data have been shown to provide a breed-level genetic resolution within modern cattle and thus a more nuanced picture of genetic variation across Europe (Bovine HapMap Consortium, 2009;Gautier et al, 2010;Edwards et al, 2011). Therefore, where possible, extension of nuclear DNA-based studies from extant populations to archaeological specimens will greatly help our understanding of ancient population affinities and local domestication events.…”