Researcher Part of International Pig Genome Sequencing

The study, conducted by the International Swine Genome Sequencing Consortium, provides a genetic comparison of the domesticated pig and its wild cousins.

The research, described in the cover article of the Nov. 15 issue of the journal Nature, offers clues about how the animal evolved. The article is available at http://psu.ag/SHjXHu.

Wansheng Liu, associate professor of animal genomics in the Department of Animal Science, participated in the study, which includes comparisons of the human, mouse, dog, horse, cow and pig genomes.

Funded mostly by the U.S. Department of Agriculture and the National Pork Board, the study promises to expand the usefulness of the pig model in human health and biomedical research, according to Liu.

"The project found variants in 112 genes in the pig genome that were identical to variants implicated in human diseases, including aberrations associated with obesity, diabetes, dyslexia, Parkinson's disease and Alzheimer's disease," he said.

"The sequencing of the pig genome represents a remarkable international initiative involving many universities and research centers worldwide."

Liu and his team at Penn State were involved in the construction of a high-resolution gene map with about 10,000 DNA markers. This map serves as a "scaffold" for pig genome sequence assembly and gene annotation, he noted.

The genome of the common farm pig was compared to the genetic makeup of 10 wild boars from locations in Europe and Asia. The genetic evidence found that the pig emerged in Southeast Asia and expanded into Europe before starting to become domesticated about 10,000 years ago.

"This project is a milestone in a long process that started with man's domestication of the pig to produce food," Liu said. "It offers new opportunities for animal geneticists to understand what genes do and what traits of economic importance they control to improve food production."

The comparison with other mammals' genomes found a rapid evolution of genes in the pig associated with immune response and the sense of smell. Pigs and rats have the greatest number of functional olfactory receptor genes possessed by any species, reflecting the importance of smell in a scavenging animal.

"The pig genome sequence provided us the tools to demonstrate that genes in the pig immune system are more similar to those in the human, in comparison with the genes found in the cow or mouse genomes," Liu explained.

"Researchers now have a genetic blueprint with which to integrate information on nutrition, reproduction, meat science, growth and development, and basic biology, which will benefit both production agriculture and biomedical research," he said.