Why geneticists should go down on the farm

Farm animals provide a unique opportunity to capture genes influencing multi-factorial traits, according to Leif Andersson, who presented the first plenary on Tuesday at the XIX International Congress of Genetics.

They are also excellent models for evolution, he said.

"Darwin used domestic animals and plants as proof of principle that you could change traits by selection," Andersson said. "The mutations which have been selected are those that change the character you are interested in."

The 10,000-year history of domestication means that less noise surrounds the adaptations, and the extensive phenotypic diversity both within and between breeds is a gold mine of information, he said.

Using pigs as a model, Andersson, of Uppsala University in Sweden, has looked for genes influencing the relatively recent shift to leaner animals. By crossing wild boars, with domestic strains of pigs, the researchers have been able to look at fatness traits.

He has discovered that a single nucleotide change in the region of the insulin growth factor 2 (IGF-2) gene, which is paternally imprinted, has resulted in many modern strains of pigs showing leaner phenotypes.

"For the first time we are able to pinpoint a single nucleotide mutation in a regulatory region," he said.

Andersson has now turned to chickens, using crosses between wild red junglefowl and the domestic white leghorn strain to study a broad variety of traits as diverse as body weight and feather pecking behaviour. Aiding the process will be the chicken genome, due by the end of the year.