Title: Genetic variation and differentiation of bison (Bison bison) subspecies and cattle (Bos taurus) breeds and subspecies Authors
Submitted to: Journal of Heredity
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: March 29, 2013
Publication Date: May 10, 2013
Citation: Cronin, M., Macneil, M., Ninh, V., Leesburg, V.L., Blackburn, H.D., Derr, J. 2013. Genetic variation and differentiation of bison (Bison bison) subspecies and cattle (Bos taurus) breeds and subspecies. Journal of Heredity. 104:500-509. Interpretive Summary: Two subspecies of bison are recognized in North America. Historically, Plains bison range was across much of the United States and southern Canada. Wood bison ranged across northwestern Canada. North American bison were nearly extinct in the late 1800’s, but the current population is 431,500 plains and wood bison. Most of these are in private herds with the rest being in public herds. One of the main issues for the public herds is maintaining population viability and genetic variation. Bison management needs to clarificy the genetic relationships of plains and wood bison, particularly in light of previous admixture, similar phenotypes, and the need to maintain viable effective population sizes. This study assessed genetic differentiation of plains and wood bison and compared bison subspecies with cattle breeds and subspecies. Microsatellite genotypes were obtained for 201 bison and 321 cattle. Genetic variation at the 29 polymorphic loci was greater in cattle than in bison. Results for genetic distances, cluster analysis, and STRUCTURE analysis indicate that there is a degree of differentiation of wood bison and plains bison, but that some plains bison herds are as differentiated from each other as are plains bison and wood bison herds. Results also suggest that the plains bison and wood bison should be treated and cataloged as one species and differentiated in a manner similar to livestock breeds and not at the higher taxonomic level of subspecies.
Technical Abstract: Genetic variation was quantified at 29 polymorphic microsatellite DNA loci in nine herds of plains bison (Bison bison bison), three herds of wood bison (B. b. athabascae), fourteen breeds of taurine cattle (Bos taurus taurus), and two breeds of indicine cattle (Bos taurus indicus). Genetic distances, cluster analysis and Bayesian cluster analysis were used to quantify the genetic relationship of plains bison and wood bison, with genetic variation among breeds and subspecies of cattle providing comparative measures of divergence. Genetic distances between herds of wood bison and herds of plains bison are on average greater than the average distance between the herds of plains bison, but the ranges of the genetic distances overlap and are not consistently larger between the subspecies than within the subspecies. Differentiation of wood bison and plains bison is also significantly less than that of cattle breeds and subspecies. These data, other genetic data, and historical interbreeding of the bison subspecies, do not support recognition of extant plains bison and wood bison as genetically distinct subspecies.