Genetics

Current knowledge of bovine genome

A lot of information is available on the genetics of cattle and the variability within and across breeds. The complete genome of a Hereford cow is available since 2009[1], On the genome about 22,000 genes coding for proteins have been identified. Most genes are homologous the human genes, but we do not always know their function The role of many genes are now being discovered, with an emphasis on the economically important genes for milking gift, meat quality e.g. And the pace of the discoveries is speeding up.

Mitochondrial DNA (mtDNA)

Since mitochondrial DNA (mtDNA) is present in more copies than autosomal (nuclear) DNA, the focus of the first studies of ancient Aurochs were on mtDNA. After initial reports of short mtDNA segments, the complete sequence of Aurochs mtDNA was described in 2010. From these studies it has been concluded that aurochs populations in Italy the last 30.000 years were always there also during the Ice ages, where as north of the Alps and Pyrenees aurochs disappeared during the Ice-ages and the areas were re-colonized by aurochs from eastern origins. From a recent study of the origin of our modern cattle breeds on the mtDNA it has been estimated that the maternal lineage of taurine cattle descend from ca. 80 individuals in the Fertile Crescent, the area around the rivers Eufrates and Tigris in Iraq and Syria.

Aurochs mtDNA

In 2010 for the first time the complete mtDNA sequence of an aurochs (was established (Edwards et al 2010). This sample was of British origin and belonged to the aurochs haplogroup P (derived from ‘primigenius’). The Italian Aurochs from Tuscany (Vado all’Arancio, Lari et al., 2011) as well as partial sequence of 11 other aurochs (Mona et al., 2010) belonged to the haplotype T (‘Taurine’) (Lari et.al, 2011), which is the predominant haplogroup in European taurine cattle breeds. The finding of the T haplogroup in Italian aurochs supports the view that aurochs populations in northern and southern Europe were different. There is at least the theoretical possibility that the southern European aurochs has contributed to modern cattle.

Aurochs autosomal DNA

The research groups from MacHugh (University College, Dublin) and Bradley (Trinity College, Dublin) have been able to sample and analyse the genome of one British Aurochs, from Carsington Pasture Cave in Brassington, Derbyshire, England. This specimen was radiocarbon-dated to 6,738±68 years BP. Up to now (March 2015) this material has not yet been publicized. A 770K SNP subset of the material has been made available for our research. Recently the material has been published (Park et.al., 2015).[2]

 

[1] Elsik, C.G. et al, (Bovine Genome Sequencing and Analysis Consortium) (2009). "The genome sequence of taurine cattle: a window to ruminant biology and evolution". Science 324 (5926): 522–528. doi:10.1126/science.1169588. PMC 2943200. PMID 19390049.

[2] Park et.al., 2015. Genome sequencing of the extinct Eurasian wild aurochs, Bos primigenius, illuminates the phylogeography and evolution of cattle. Genome Biology (2015) 16:234