An international group of biologists and geneticists published paper at the Public Library of Science on January 7, 2010, that used DNA sampling and satellite imaging to define the variety of origin and a possible time line for the development of dairy cattle farming in ancient Europe.
One proposed time line is as follows: "An obvious possibility is that the current Y-chromosomal haplogroup distribution reflects Neolithic immigration routes. According to archaeological evidence, the dispersal of agriculture in Europe started in Greece around 7,000 BC, moved to southern Italy circa. 6,000 BC, and then along a southern route into the western Mediterranean between 5,600 and 5,400 BC, reaching Portugal around 5,300 BC. Migration along the continental route into Poland and Germany occurred between 5,500 and 5,300 BC, reaching north-western France around 5,000 BC; southern Scandinavia, the British Isles and Ireland were reached circa. or after 4,000 BC.It is generally accepted that agriculture spread via these two routes: the Mediterranean route and the Danubian (or continental) route. Although Y1 has a clear presence in Iberian cattle, Y2 paternal lineages dominate in the present Mediterranean area. A founder effect in Danubian immigrants could have caused the dominance of Y1 in northern Europe. In this scenario, the presence of Y1 in Iberia would have resulted from movements along the Atlantic seaboard, as documented by the Neolithic archaeological record, and the presence of two haplogroups in Britain may indicate a convergence of immigrants of both routes."
Background
Diversity 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 Findings
Haplogroup 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.
Conclusions
We 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.
Author: Paul Hamaker | Source: Examiner [January 09, 2011]