Researchers have sequenced the complete genome of sheep. The study could help scientists find genes unique to the animals and chart their evolutionary history.

Sheep are an important source of meat, milk and wool products in several parts of the world such as Australia and New Zealand. The new study could help breeders better manage sheep stocks.

The genome was sequenced by an international team of researchers, including Jo-Ann Stanton at the University of Otago. The team worked on the project for eight years and their findings is published in the journal Science.

The lineage that gave rise to modern sheep split from other ruminants some 2.6 million years ago during the late Neogene period, the study showed.

"We investigated the completed genome to determine which genes are present in a process called gene annotation, which resulted in an advanced understanding of the genes involved in making sheep the unique animals that they are," Dr Brian Dalrymple at Commonwealth Scientific and Industrial Research Organisation (CSIRO), said in a news release.

"Given the importance of wool production, we focused on which genes were likely to be involved in producing wool. We identified a new pathway for the metabolism of lipid in sheep skin, which may play a role in both the development of wool and in the efficient production of wool grease (lanolin)."

Researchers created a map of Texel sheep, a breed originally from the Netherlands. The team identified genes related to sheep's' unique digestive system and its ability to maintain the thick wool.

Sheep along with other ruminants such as deer and cattle have a unique digestive organ called the rumen, which turns plant material into protein. The new sheep genome could help researchers understand the rumen in detail, according to a news release.

The team also compared the evolutionary history of sheep and compared it with other mammals. They created a phylogenetic tree to compare genomes of sheep and other ruminants such as deer and cattle.