Animal Molecular Breeding, 2025, Vol.15, No.1, 39-48 http://animalscipublisher.com/index.php/amb 40 2 Evolutionary Background of Canids 2.1 Divergence and phylogenetic relationships among wolves, coyotes, and dogs The evolution of canids is marked by extensive divergence and hybridization events. The common ancestors of wolves (Canis lupus), coyotes (Canis latrans), and domestic dogs (Canis familiaris) diverged into distinct evolutionary lines. High-throughput genotyping has also revealed that there are some hierarchical population units in gray wolves and coyotes that are consistent with geographic and ecological differentiation (Vonholdt et al., 2011). Hybridization has been seen between the two species, and coyotes and wolves create large hybrid swarms, particularly in regions like Ohio, where coyotes exhibit varying degrees of admixture with wolves and domestic dogs. Hybridization introduced adaptive alleles into the coyote gene pool, and it facilitated them in invading new geographic ranges and food niches (Monzón et al., 2014). 2.2 Domestication of dogs and its genetic implications on behavior Domestication of dogs from wolves has put tremendous genetic and behavioral loads. Domestication notwithstanding, dogs and wolves are closely related genetically, great gene expression distinctions have resulted from domestication, particularly in the brain. Experiments prove that there is evidence of neuropeptide expression change of neuropeptides such as CALCB and NPY in the hypothalamus in dogs, which may be due to intense selection for specific behavior during domestication (Saetre et al., 2004). Moreover, structural variations like copy number variants (CNVs) were discovered in dogs and play a role in growth and neurological functions and depict domestication selection pressure (Ramírez et al., 2014). These genetic changes have been responsible for some of the differences in behavior between the domestic dog and its forebears, the wolves, e.g., being trainable with ease and accommodating being less afraid (Smith et al., 2017). 2.3 Adaptive traits specific to wolves and coyotes in the wild Wolves and coyotes also have adaptive features that enable them to live in their habitats. For instance, hybridization with coyotes has resulted in wolf-like features in coyotes, particularly where deer densities are high, suggesting local adaptation due to natural selection (Monzón et al., 2014). The Himalayan and the Tibetan wolves have, in return, adapted to high-altitude environments through genetic introgression from an ancient, albeit neglected, wolf-like species. Introgression has provided adaptive advantages, such as the EPAS1 haplotype, associated with high-altitude adaptation (Wang et al., 2020). Such adaptations highlight the complex interplay between genetic diversity and environmental pressures in the shaping of evolutionary histories of wild canids. 3 Genetic Basis of Behavioral Traits 3.1 Identification of key behavioral genes in canids A number of significant genes have been discovered by research that are accountable for canid behavior traits. Genome-wide association studies (GWAS) have uncovered major loci that are linked to herding, predation, temperament, and trainability in dogs. For instance, genes including THOC1, ASIC2, MSRB3, LLPH, RFX8, and CHL1 are accountable for herding behavior, while JAK2, MEIS1, and LRRTM4 are accountable for predation behavior (Shan et al., 2021). Furthermore, 11 loci were highly associated with a variety of behaviors, including howling frequency and sociability to humans (Morrill et al., 2022). The study releases the complex genetic foundation of canid behavior under both natural and artificial selection. 3.2 Commonalities and differences in genetic markers across species Comparative genomic studies have been able to show similarities and differences in genetic markers in canid species. For example, the IGF1 gene size polymorphism region shows a single base substitution that differentiates small and large canids, the “small” one being more prevalent in small breeds while the "large" one in wolves and large dogs (Jordan, 2022). Furthermore, hybridization studies, such as the eastern coyote (hybrid coyote, wolf, and dog), have intermediate morphological traits and greater variation in hybrids, which express shared genetic markers among species (Zdjelar et al., 2021). Specialized adaptations, such as African wild dog, however, express species-specific genetic variation enforced by evolutionary pressures (Chavez et al., 2019).
RkJQdWJsaXNoZXIy MjQ4ODYzNA==