Using genetic data to characterize dispersal, relatedness and parentage in the collared peccary (Pecari tajacu)
Abstract
Heretofore, little was known of the population genetic structure, dispersal, genetic mating system or relationships of the collared peccary (Pecari tajacu). I sampled 268 individuals from 31 herds in 3 Texas populations. I haplotyped peccaries at a 449bp control region locus within the mitochondrial genome. Analysis of mtDNA haplotype distribution patterns across Texas indicates that P. tajacu has recently expanded its range, a result congruent with historical accounts of the recent colonization by collared peccaries of the American southwest. I utilized mtDNA haploype data to estimate sex-specific natal dispersal rates through sex-specific comparisons of genetic variation among social groups. AMOVA analyses yielded fixation index values for females which were significantly larger than values for males. I also calculated a rate of male dispersal among social groups of 0.37. These results indicate that mtDNA can be used to infer instantaneous dispersal behavior for both sexes, despite a pattern of matrilineal inheritance. Collared peccaries exhibit several traits that differentiate them from suids, including a mixed-sex grouping pattern and sexual monomorphism. There has been debate concerning the importance of social dominance in maximizing male reproductive success. I used 11 polymorphic microsatellites (6 of which I developed for P. tajacu via cloning) to produce a multi-locus genotype for all individuals. I tested genetic relationships among adults and assigned parents to 75 offspring. My results indicate that herds comprised a mixture of relatives and non-relatives of both sexes. I used pairwise relatedness (r) estimates between adult males and adult females within herds to classify 38% of males as dispersers, a rate comparable to that inferred from the mtDNA analysis. Relationship analyses also revealed a low degree of female dispersal, a result that clarifies the source of the modest degree of female mtDNA haplotype admixture females within herds. Parentage data suggest that males either disperse multiply or successfully father offspring in neighboring herds. Multiple males sire offspring within a herd, and there was no evidence for reproductive skew in either sex. Clearly, neither males nor females monopolize reproductive success, thus competition may play a smaller role mating system than was previously suggested.
Degree
Ph.D.
Advisors
Waser, Purdue University.
Subject Area
Ecology|Genetics
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