WASHINGTON (Reuters) - An international team of researchers said Monday it had mapped the DNA of a domestic pig, work they say could help lead to better breeding techniques as well as improve vaccines against diseases such as swine flu.

They plan to look for genes useful in pork production and immunity in pigs, which are similar in size to humans. And, like humans, they catch influenza very easily.

"Understanding the swine genome will lead to health advancements in the swine population and accelerate the development of vaccinations for pigs," said Roger Beachy, Director of the U.S. Department of Agriculture's National Institute of Food and Agriculture.

"This new insight into the genetic makeup of the swine population can help reduce disease and enable medical advancements in both pigs and humans," Beachy said in a statement.

"The pig is a unique animal that is important for food and that is used as an animal model for human disease," added Larry Schook of the University of Illinois in Champaign, who helped direct the project.

"And because the native wild animals are still in existence, it is a really exciting animal to look at to learn about the genomic effects of domestication."

The pandemic H1N1 swine flu virus originated in pigs and evidence suggests it can be passed from humans to pigs and back again. Pigs are also susceptible to many other strains of influenza.

(Reporting by Maggie Fox; Editing by Eric Walsh)