Y‐chromosome evidence supports asymmetric dog introgression into eastern coyotes

Abstract

Hybridization has played an important role in the evolutionary history of Canis species in eastern North America. Genetic evidence of coyote–dog hybridization based on mitochondrial DNA (mtDNA) is lacking compared to that based on autosomal markers. This discordance suggests dog introgression into coyotes has potentially been male biased, but this hypothesis has not been formally tested. Therefore, we investigated biparentally, maternally, and paternally inherited genetic markers in a sample of coyotes and dogs from southeastern Ontario to assess potential asymmetric dog introgression into coyotes. Analysis of autosomal microsatellite genotypes revealed minimal historical and contemporary admixture between coyotes and dogs. We observed only mutually exclusive mtDNA haplotypes in coyotes and dogs, but we observed Y-chromosome haplotypes (Y-haplotypes) in both historical and contemporary coyotes that were also common in dogs. Species-specific Zfy intron sequences of Y-haplotypes shared between coyotes and dogs confirmed their homology and indicated a putative origin from dogs. We compared Y-haplotypes observed in coyotes, wolves, and dogs profiled in multiple studies, and observed that the Y-haplotypes shared between coyotes and dogs were either absent or rare in North American wolves, present in eastern coyotes, but absent in western coyotes. We suggest the eastern coyote has experienced asymmetric genetic introgression from dogs, resulting from predominantly historical hybridization with male dogs and subsequent backcrossing of hybrid offspring with coyotes. We discuss the temporal and spatial dynamics of coyote–dog hybridization and the conditions that may have facilitated the introgression of dog Y-chromosomes into coyotes. Our findings clarify the evolutionary history of the eastern coyote.

Assessment of coyote–wolf–dog admixture using ancestry‐informative diagnostic SNPs

“…A recent analysis of maternally inherited mtDNA and paternally inherited Y‐chromosome markers revealed that the asymmetric introgression of dog genes into north‐eastern coyotes is mediated by male dogs (Wheeldon et al . ). Hybridization of European and African wolves with dogs is also consistently mediated by male dogs and female wolves (Gottelli et al .…”

“…Using twelve autosomal microsatellites, Wheeldon et al . () recently found that coyotes in south‐eastern Ontario have on average 2.3% dog ancestry. Together, these results suggest a limited, but appreciable, amount of coyote–dog hybridization in the recent past (11–24 generations, estimated by vonHoldt et al .…”

Dobzhansky-Muller incompatibilities, dominance drive, and sex-chromosome introgression at secondary contact zones: A simulation study

“…) or Canis species (where dog Y chromosomes are introgressed into coyote populations; Wheeldon et al. ). Cline shifts might possibly also account for the patterns found in poplars, if the lack of differentiation at sex‐linked markers results from the massive introgression of P. alba sex chromosomes into the genomic background of P. tremula (Stölting et al.…”

“…The preferential introgression of Y chromosomes from dog to coyote (Wheeldon et al. ), for instance, might be driven by a Y‐A incompatibility, assuming that the dog allele for the autosomal locus involved in the incompatibility is dominant over the coyote allele, and that male migration is strong relative to selection.…”

High genomic diversity and candidate genes under selection associated with range expansion in eastern coyote (Canis latrans) populations

“…In particular, red wolves are believed to be extirpated outside of the North Carolina recovery area, but hybridization between red wolves and coyotes is well documented within that area (Bohling et al, 2016;Hinton, Gittleman, Manen, & Chamberlain, 2018). Further, several previous studies have also shown that eastern coyote populations have interbred with domestic dogs (Adams, Leonard, & Waits, 2003;Wilson, Rutledge, Wheeldon, Patterson, & White, 2012;Wheeldon, Rutledge, Patterson, White, & Wilson, 2013;Monzõn, Kays, & Dykhuizen, 2014). While there is evidence that these hybridization events have been adaptive (vonHoldt et al, 2016), it is important to note that the full genome-wide consequences and the geographic extent of interspecies hybridization have not been documented throughout the entire eastern range.…”