MBE Advance Access published online on April 7, 2008
Molecular Biology and Evolution, doi:10.1093/molbev/msn082
Research Article |
Coyotes demonstrate how habitat specialization by individuals of a generalist species can diversify populations in a heterogeneous ecoregion
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* Veterinary Genetics Laboratory, University of California, Davis, Davis, CA 95616-8744, USA
Department of Population Health and Reproduction, School of Veterinary Medicine, University of California, Davis, Davis, CA 95616-8744, USA
Department of Biological Sciences, California State University, Sacramento, Sacramento, CA 95819, USA
Correspondence: Benjamin N. Sacks, Veterinary Genetics Laboratory, University of California, One Shields Ave/Old Davis Rd., Davis, CA 95616-8744, USA, Fax: +1-530-752-3556; E-mail: bnsacks{at}ucdavis.edu
Received for publication November 20, 2007. Revision received March 24, 2008. Revision received March 28, 2008. Accepted for publication March 31, 2008.
The tendency for individuals to disperse into habitat similar to their natal habitat has been observed in a wide range of species, although its population genetic consequences have received little study. Such behaviour could lead to discrete habitat-specific population subdivisions even in the absence of physical dispersal barriers or habitat gaps. Previous studies of coyotes have supported this hypothesis in a small region of California, but its evolutionary significance ultimately depends on the extent and magnitude of habitat-specific subdivision. Here, we investigated these questions using autosomal, Y-chromosome, and mitochondrial markers and >2,000 coyotes from a broad region, including two adjacent ecoregions with contrasting levels of habitat heterogeneity–the California Floristic Province (heterogeneous landscape) and the Desert-Prairie Ecoregion (homogeneous landscape). Consistent with predictions, we found a close correspondence between population genetic structure and habitat subdivisions throughout the California Floristic Province and virtual panmixia over the larger Desert-Prairie Ecoregion. Conversely, although genetic diversity was similar in these two ecoregions overall, it was lower within sites of the California Floristic Province, as would be the expected consequence of greater genetic drift within subregions. The magnitude of habitat-specific genetic subdivisions (i.e., genetic distance) in the California Floristic Province varied considerably, indicating complexity (e.g., asymmetric gene flow or extinction/recolonization), but, in general, was higher than that due to geographic distance or recent human-related barriers. Because habitat-specific structure can enhance a species’ adaptive potential and resilience to changing environments, these findings suggest the California Floristic Province may constitute an evolutionarily important portion of the range for coyotes and sympatric species exhibiting habitat-specific population structure.
Key Words: Canis latrans • gene flow • genetic diversity • genetic structure • habitat • isolation-by-distance