title: Inbreeding avoidance drives consistent variation of fine-scale genetic structure caused by dispersal in the seasonal mating system of Brandt's voles.
abstract: Inbreeding depression is a major evolutionary and ecological force influencing population dynamics and the evolution of inbreeding-avoidance traits such as mating systems and dispersal. Mating systems and dispersal are fundamental determinants of population genetic structure. Resolving the relationships among genetic structure, seasonal breeding-related mating systems and dispersal will facilitate our understanding of the evolution of inbreeding avoidance. The goals of this study were as follows: (i) to determine whether females actively avoided mating with relatives in a group-living rodent species, Brandt's voles (Lasiopodomys brandtii), by combined analysis of their mating system, dispersal and genetic structure; and (ii) to analyze the relationships among the variation in fine-genetic structure, inbreeding avoidance, season-dependent mating strategies and individual dispersal. Using both individual- and population-level analyses, we found that the majority of Brandt's vole groups consisted of close relatives. However, both group-specific FISs, an inbreeding coefficient that expresses the expected percentage rate of homozygosity arising from a given breeding system, and relatedness of mates showed no sign of inbreeding. Using group pedigrees and paternity analysis, we show that the mating system of Brandt's voles consists of a type of polygyny for males and extra-group polyandry for females, which may decrease inbreeding by increasing the frequency of mating among distantly-related individuals. The consistent variation in within-group relatedness, among-group relatedness and fine-scale genetic structures was mostly due to dispersal, which primarily occurred during the breeding season. Biologically relevant variation in the fine-scale genetic structure suggests that dispersal during the mating season may be a strategy to avoid inbreeding and drive the polygynous and extra-group polyandrous mating system of this species.
authors.affiliation: The State Key Laboratory for Biology of Plant Diseases and Insect Pests, Institute of Plant Protection, Chinese Academy of Agricultural Sciences, Beijing, China. lxiaohui2000@163.com
authors.forename: Xiao Hui
authors.initials: XH
authors.lastname: Liu
authors.forename: Ling Fen
authors.initials: LF
authors.lastname: Yue
authors.forename: Da Wei
authors.initials: da W
authors.lastname: Wang
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.forename: Lin
authors.initials: L
authors.lastname: Cong
mesh_terms: D000818:Animals; D003411:Arvicolinae / Q000235:genetics*; D005260:Female; D014644:Genetic Variation; D005828:Genetics, Population; D007178:Inbreeding; D008297:Male; D018895:Microsatellite Repeats; D010334:Paternity; D011157:Population Dynamics; D012098:Reproduction / Q000235:genetics; D012621:Seasons; D012726:Sexual Behavior, Animal