ARS | Publication request: GENETIC RELATIONSHIPS BETWEEN FERAL CATTLE FROM CHIRIKOF ISLAND, ALASKA, AND OTHER BREEDS

Submitted to: Animal Genetics
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: November 24, 2006
Publication Date: May 20, 2007
Repository URL: http://ars.usda.gov/SP2UserFiles/Place/54340000/Publications/AnimGenetics38-193-197.pdf
Citation: MacNeil, M.D., Cronin, M.A., Blackburn, H.D., Richards, C.M., Lockwood, D.R., Kantanen, J., Alexander, L.J. 2007. Genetic relationships between feral cattle from Chirikof Island, Alaska, and other breeds. Animal Genetics 38:193-197.

Interpretive Summary: Cattle have been present on Chirikof Island off the coast of Alaska for at least the last century and possibly before the purchase of Alaska from Russia. These cattle have survived with minimal managerial intervention for much of this time, but little is known of there usefulness or genetic adaptation to the environment. The objective of this research was to characterize the genetic variation present in the Chirikof Island population and to establish its degree of uniqueness relative to breeds more commonly used in commercial production. In two related studies of microsatellite marker data, among breed differentiation was comparable. To assess the likely source breeds on Chirikof Island herd, we used two complementary approaches to examine the genetic contribution of potential progenitor breed from North America and Siberia. Genetic diversity among Chirikof, North American and Yakut breeds was displayed both as a nearest neighbor branching tree and as a population network. The nearest neighbor breeds to the Chirikof population within this network were included in a Bayesian assignment test. The test showed stable clustering of genotypes among these breeds indicating that the Chirikof Island population while showing relatedness to three North American breeds and Yakut, is unique and strongly differentiated. Based on these results, it might be argued that germplasm from Chirikof Island should be preserved and used in future research to characterize its usefulness as the degree to which these cattle are adapted to local conditions, diseases, forage resources, climate and so forth is presently unknown.

Technical Abstract: The origin of cattle on Chirikof Island, off the coast of Alaska, is not well documented, but is thought to include Russian stock brought by colonists in the 1700-1800’s, augmented by U.S. stock in the 1900’s. We assessed genetic differentiation of cattle isolated on Chirikof Island from several breeds commonly used for commercial production in North America, breeds popularly believed to have contributed to the Chirikof Island population, and Siberian Yakut cattle. In two related studies of microsatellite data (one using 34 markers and the other 15 different markers) FST statistics were generated for two sets of breeds (the first comparing North American breed and Chirikof and the second comparing North American, Siberian and Chirikof populations). Among breed differentiation, using FST statistics, in the two datasets were comparable. The values ranged from 0.06 to 0.23 with an average of 0.14. To assess the likely source breeds on Chirikof Island herd, we used two complementary approaches to examine the genetic contribution of potential progenitor breed from North America and Siberia. Genetic diversity among Chirikof, North American and Yakut breeds was analyzed using an AMOVA approach and displayed as a population network. The nearest neighbor breeds to the Chirikof population within this network were included in a Bayesian assignment test. The test showed stable clustering of genotypes among these breeds indicating that the Chirikof Island population while showing relatedness to three North American breeds and Yakut, is unique and strongly differentiated.