Abstract
BackgroundDomestication of the rabbit (Oryctolagus cuniculus) has led to a multi-purpose species that includes many breeds and lines with a broad phenotypic diversity, mainly for external traits (e.g. coat colours and patterns, fur structure, and morphometric traits) that are valued by fancy rabbit breeders. As a consequence of this human-driven selection, distinct signatures are expected to be present in the rabbit genome, defined as signatures of selection or selective sweeps. Here, we investigated the genome of three Italian commercial meat rabbit breeds (Italian Silver, Italian Spotted and Italian White) and 12 fancy rabbit breeds (Belgian Hare, Burgundy Fawn, Champagne d’Argent, Checkered Giant, Coloured Dwarf, Dwarf Lop, Ermine, Giant Grey, Giant White, Rex, Rhinelander and Thuringian) by using high-density single nucleotide polymorphism data. Signatures of selection were identified based on the fixation index (FST) statistic with different approaches, including single-breed and group-based methods, the latter comparing breeds that are grouped based on external traits (different coat colours and body sizes) and types (i.e. meat vs. fancy breeds).ResultsWe identified 309 genomic regions that contained signatures of selection and that included genes that are known to affect coat colour (ASIP, MC1R and TYR), coat structure (LIPH), and body size (LCORL/NCAPG, COL11A1 and HOXD) in rabbits and that characterize the investigated breeds. Their identification proves the suitability of the applied methodologies for capturing recent selection events. Other regions included novel candidate genes that might contribute to the phenotypic variation among the analyzed breeds, including genes for pigmentation-related traits (EDNRA, EDNRB, MITF and OCA2) and body size, with a strong candidate for dwarfism in rabbit (COL2A1).ConclusionsWe report a genome-wide view of genetic loci that underlie the main phenotypic differences in the analyzed rabbit breeds, which can be useful to understand the shift from the domestication process to the development of breeds in O. cuniculus. These results enhance our knowledge about the major genetic loci involved in rabbit external traits and add novel information to understand the complexity of the genetic architecture underlying body size in mammals.
Highlights
Domestication of the rabbit (Oryctolagus cuniculus) has led to a multi-purpose species that includes many breeds and lines with a broad phenotypic diversity, mainly for external traits that are valued by fancy rabbit breeders
Within‐breed genomic parameters In total, 660 rabbits from 15 breeds that are characterized by different external features or purposes were genotyped
The average withinbreed minor allele frequency (MAF) ± s.d. ranged from 0.178 ± 0.160 in the Ermine breed to 0.266 ± 0.152 in the Italian White breed
Summary
Domestication of the rabbit (Oryctolagus cuniculus) has led to a multi-purpose species that includes many breeds and lines with a broad phenotypic diversity, mainly for external traits (e.g. coat colours and patterns, fur structure, and morphometric traits) that are valued by fancy rabbit breeders. Domestication of the rabbit occurred after a first genetic bottleneck that involved the wild subpopulations from which the domestic lines were derived, accompanied by limited recurrent introgression from the wild types [6, 7] This resulted in only slightly modified allele frequencies at many loci between the wild and domestic rabbit populations, which suggests that the domestication process had a relatively weak effect on standing genetic variation in many regulatory regions of the genome [6]. These changes occurred mainly in genes that are involved in brain and neuronal development, which indicates that the resulting modified behaviour traits were important for the domestic rabbit to adapt to the human environment. In this species, the domestication process relied on derived genetic material, which contained variants that determine favourable behavioral traits and facilitate handling and breeding [6]
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