THE recently completed map of the entire cattle genome should enable scientists to rapidly speed up genetic gains in beef and dairy cattle and other livestock species.
The publication at the end of last month of the results of the six-year international project to decipher the complete genetic blueprint of cattle is a landmark in livestock genetics, which will lead to improved meat and milk production and disease resistance.
About 300 scientists from 25 countries were involved in the work.It was the first time the genome of a ruminant animal had been sequenced and analysed, and it was done on samples from a Hereford cow called L 1 Dominette 01449 based at a United States Department of Agriculture research laboratory in Montana.
New Zealand has been heavily involved in the project through AgResearch, Meat & Wool NZ and DairyNZ, and contributed US$1 million of the US$53 million costs of the Bovine Genome Sequencing and Analysis Consortium.
AgResearch scientist John McEwan, who is also involved in the international effort to map the sheep genome, said New Zealand’s contribution gave it early access to data and influence in the decision to prioritise the bovine genome over that of other species.
“The importance of this should not be underestimated as New Zealand will benefit greatly from this research due to its economic dependence on products from ruminants.’’
While the dairy industry was already making genetic gains from the research, he said the beef industry had been slower to benefit. “But a number of systems influenced by the research are beginning to emerge that will improve the rate of genetic gain in meat yield and quality, feed efficiency and disease resistance.’’
The sequencing found that cattle have about 22,000 genes, which is typical for a mammal, but they have an unusually large number of genes not found in other species.
Of particular interest is an important complement of genes in cattle dedicated to the immune system, giving them resistance to a wider range of micro-organisms than humans can cope with. This is likely to have implications for human health research.
Scientists also compiled draft genetic sequences for other breeds of cattle for comparison. These were from Holstein, Angus, Jersey, Limousin, Norwegian Red and Brahman.
Like other mammals, including humans, duplications of segments of DNA were found in different locations on the genome.
These can sometimes result in unwanted mutations.
Beef genetics co-ordinator for Meat & Wool NZ Russell Priest said the cattle genome information was going to be “hugely powerful”.
The major importance for his work would be that it would locate and identify superior animals and the various traits of economic importance.
“It’s early days yet. The technology to find these markers is vastly improved from what it was even three years ago. No doubt it will improve more rapidly as time goes by.’’
The new genomic information would enable researchers to search for far more variations than previously, and do it more quickly.
He said lethal mutations in cattle continued to arise. The new information would help identify these animals early on so they could be culled.
Mr Priest said it was really important genetic information was validated in defined populations. “The variation might be present in one population, but might have an entirely different effect in another population.’’
He said commercialised genetic markers had been pulled off the market because they hadn’t been widely validated.
The technology was now available to incorporate the new genomic information into the current EBVs. They would be known as marker assisted EBVs. “We certainly won’t do away with EBVs, not in the immediate future anyway.’’
howardkeene@clear.net.nz
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