Denver, Colo. -- A large international team of researchers has completed the sequence of the sheep genome, to be published in Science today in a study entitled, "The Sheep Genome Illuminates Biology of the Rumen and Lipid Metabolism." The completion of the genome is the culmination of eight years of work by a team of more than 70 researchers from 26 institutions located in eight countries around the world.
"The release of the sheep genome assembly is the culmination of a very large international effort," acknowledges Noelle Cockett, Ph.D., Provost of Utah State University (USU) and Professor in the Department of Animal, Dairy and Veterinary Sciences at USU. "I am honored to be part of the project and I appreciate the American Sheep Industry's support of the project and of my involvement throughout the years. The assembly would not have been possible without the encouragement and engagement of the U.S. sheep producers."
The U.S. components of the project were undertaken at USU, Baylor College of Medicine, U.S. Department of Agriculture's Agricultural Research Service and Washington State University.
This work will accelerate research on all kinds of sheep traits--from reproduction and lamb growth to wool quality, milk yield, methane production and disease resistance. These applications will lead to better breeding strategies and new approaches to sheep management. The study also enhances understanding of genes in other species like cows, goats and deer.
The specific findings include the DNA sequence of sheep, the locations of the genes and an extensive index showing where in the body each of the genes is active. In the past, researchers studying particular traits had to do extensive DNA sequencing--often over months and years--to understand just a few genes at a time. Now the complete set is available in seconds.
Lead researcher Brian Dalrymple, Ph.D., from the Commonwealth Scientific and Industrial Research Organization (CSIRO), Australia's national science agency, describes the impact of the work: "Sheep are a major source of the world's meat, milk and wool, and this project has for the first time collected and assembled the DNA sequence and undertaken a large study of where the genes are expressed.
"Given the importance of wool production, we looked to see what genes were likely to be involved. This identified a novel 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)," said Dalrymple.
Another key finding from the study involved the rumen, which is an essential organ for sheep to convert plant forage into animal protein. Sheep and some other livestock species have a rumen as well as a stomach to help with forage digestion. A number of novel genes have been identified that are only active in the rumen. Finding these genes is the first step toward a better understanding of how sheep process forage so efficiently.
Finally, the sheep genome will assist in advancing human and veterinary medicine. The resources built by the team will provide a strong foundation for the detailed exploration of the similarities and differences between sheep, humans and other animals at the molecular level. This will enable improved medical treatments for a number of conditions, including sepsis and asthma.
"The availability of the genome assembly will improve the efficiency and timeliness of genetic and genomic studies in sheep," Cockett continues. "I anticipate an increasing number of discoveries coming out of the assembly that will translate into improvements for the sheep industry."
"In my opinion, this is scientific collaboration at its best," suggests Clint Krebs, president of the American Sheep Industry Association. "Our industry is very proud of their hard work and especially of the key role U.S. researchers and the leadership of Noelle Cockett played in the process.
"The publication of this discovery dawns a new day for sheep production in the United States and globally; besides bringing to light a better understanding of basic biology, the opportunities for improvements in production efficiency of lamb and wool, plus health and disease management, are almost limitless."
Specific U.S. contributors include Noelle Cockett and Chunhua Wu (Utah State University), Kim C. Worley, Richard A. Gibbs, Donna M. Muzny, Michael E. Holder, Shalini N. Jhangiani, Divya Kalra, Christie L. Kovar, Sandra L. Lee, and Tittu Mathew (Baylor College of Medicine, Human Genome Sequencing Center) and Margaret A. Highland and Stephen N. White (USDA-ARS Animal Disease Research Unit and Washington State University). Brad Freking (USDA-ARS Roman L. Hruska U.S. Meat Animal Research Center) contributed sheep samples used for sequencing.
ASI is a national trade organization supported by 46 state sheep associations, benefiting the interests of more than 79,500 sheep producers.