title: Spatial patterns of immunogenetic and neutral variation underscore the conservation value of small, isolated American badger populations.
abstract: Small and isolated populations often exhibit low genetic diversity due to drift and inbreeding, but may simultaneously harbour adaptive variation. We investigate spatial distributions of immunogenetic variation in American badger subspecies (Taxidea taxus), as a proxy for evaluating their evolutionary potential across the northern extent of the species' range. We compared genetic structure of 20 microsatellites and the major histocompatibility complex (MHC DRB exon 2) to evaluate whether small, isolated populations show low adaptive polymorphism relative to large and well-connected populations. Our results suggest that gene flow plays a prominent role in shaping MHC polymorphism across large spatial scales, while the interplay between gene flow and selection was stronger towards the northern peripheries. The similarity of MHC alleles within subspecies relative to their neutral genetic differentiation suggests that adaptive divergence among subspecies can be maintained despite ongoing gene flow along subspecies boundaries. Neutral genetic diversity was low in small relative to large populations, but MHC diversity within individuals was high in small populations. Despite reduced neutral genetic variation, small and isolated populations harbour functional variation that likely contribute to the species evolutionary potential at the northern range. Our findings suggest that conservation approaches should focus on managing adaptive variation across the species range rather than protecting subspecies per se.
authors.affiliation: Forensic Science Department Trent University Peterborough ON Canada; Natural Resources DNA Profiling and Forensics Centre Trent University Peterborough ON Canada; Present address: CONACYT Instituto de Ecología A.C.Centro Regional del Bajío Avenida Lázaro Cárdenas 253 Pátzcuaro Michoacán 61600 México.
authors.forename: Yessica
authors.initials: Y
authors.lastname: Rico
authors.affiliation: Ontario Badger Project Guelph ON Canada; Department of Integrative Biology University of Guelph Guelph ON Canada.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Ethier
authors.affiliation: Forensic Science Department Trent University Peterborough ON Canada; Natural Resources DNA Profiling and Forensics Centre Trent University Peterborough ON Canada.
authors.forename: Christina M
authors.initials: CM
authors.lastname: Davy
authors.affiliation: Ontario Badger Project Guelph ON Canada.
authors.forename: Josh
authors.initials: J
authors.lastname: Sayers
authors.affiliation: Ecosystems Protection & Sustainability Branch Ministry of Environment Victoria BC Canada.
authors.forename: Richard D
authors.initials: RD
authors.lastname: Weir
authors.affiliation: Central Michigan University Mount Pleasant MI USA.
authors.forename: Bradley J
authors.initials: BJ
authors.lastname: Swanson
authors.affiliation: Wildlife Research and Monitoring Section Ministry of Natural Resources & Forestry Peterborough ON Canada.
authors.forename: Joseph J
authors.initials: JJ
authors.lastname: Nocera
authors.affiliation: Forensic Science Department Trent University Peterborough ON Canada; Natural Resources DNA Profiling and Forensics Centre Trent University Peterborough ON Canada.
authors.forename: Christopher J
authors.initials: CJ
authors.lastname: Kyle
keywords: Mustelids; conservation genetics; gene flow; local adaptation; northern range; selection; small isolated populations