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Unravelling the cattle genome - a global initiative

A paper entitled “Meta-analysis of genome-wide association studies for the stature of cattle reveals numerous common genes that regulate size in mammals”, which is co-authored by Teagasc quantitative geneticists Dr Deirdre Purfield and Dr Donagh Berry, has just been published by Nature Genetics.

Unravelling the cattle genome - a global initiative
Teagasc geneticists Dr Deirdre Purfield and Dr Donagh Berry have been analysing the cattle genome for genes that regulate size.

Unravelling the cattle genome - a global initiative

A paper entitled “Meta-analysis of genome-wide association studies for the stature of cattle reveals numerous common genes that regulate size in mammals”, which is co-authored by Teagasc quantitative geneticists Dr Deirdre Purfield and Dr Donagh Berry, has just been published by Nature Genetics.

The study was the result of a collaboration between 31 different academic institutes and industry partners from 13 different countries. Each country performed its own analyses with the results subsequently combined in a meta-analysis based on 25.4 million DNA fragments from 58,265 cattle representing eight different Bos taurus breeds. All animals had measures of genetic merit for stature which was chosen because it is under strong genetic control, is measured relatively consistently globally in cattle, and is a topic of active research in human genomics. The analyses undertaken by the Teagasc geneticists were based on over 5,000 dairy animals and over 20,000 beef animals. Results from the combined analyses revealed that the genetic architecture of stature in cattle is influenced by a very large number of DNA variants and is more similar to that in humans than it is to dogs. The 163 detected significant DNA regions in the study with greatest association with stature in cattle explained at most 13.8% of the variability. This is less than, but of a similar level of magnitude to the percentage (~16%) of variability in human height explained by significant DNA variants; the results are substantially different to that reported in dogs, for example, where six DNA variants were sufficient to explain 25% and 72% of within breed variation. Considerable overlap existed in the genomic regions detected in the study to be associated with stature in humans and other mammals. Many of the variants in the cattle study likely arose prior to domestication as 23% were present in various forms in an Auroch genome (an extinct species of large wild cattle that inhabited Europe, Asia, and North Africa and an ancestor of modern cattle).

Teagasc geneticist and co-author on the paper, Dr Deirdre Purfield said: “The power of international collaboration for elucidating the genomic architecture of traits is now well-recognised. We are seeing strong growth in open access data and software, as well as greater multi-institution consortia in pursuit of advancing science, in particular advancing genetic gain in domesticated species and using these as model organisms for human genomics research. The strength of such initiatives in unraveling the genomic construction of traits is particularly strong when data from diverse breeds are used.” The results support the hyphothesis that there are numerous common genes affecting size in mammals. Teagasc geneticists are already part of similar large global initiatives for other complex performance traits with the aim of developing value-added tailored management strategies as well as possibly improve the accuracy of predicting the future performance of an animal using DNA technology.

Funding for the study originated from the Research Stimulus Fund, Department of Agriculture, Food and the Marine (MultiGS project), and the Science Foundation Ireland Investigator Programme (PrecisionBreeding project).