Exploring the genomic resources and analysing the genetic diversity and population structure of Chinese indigenous rabbit breeds by RAD-seq

Chinese indigenous rabbits have distinct characteristics, such as roughage resistance, stress resistance and environmental adaptability, which are of great significance to the sustainable development of the rabbit industry in China. Therefore, it is necessary to study the genetic diversity and population structure of this species and develop genomic resources.

In this study, we used restriction site-associated DNA sequencing (RAD-seq) to obtain 1,006,496 SNP markers from six Chinese indigenous rabbit breeds and two imported rabbit breeds. Jiuyishan and Fujian Yellow rabbits showed the highest nucleotide diversity (π) and decay of linkage disequilibrium (LD), as well as higher observed heterozygosity (Ho) and expected heterozygosity (He), indicating higher genetic diversity than other rabbits. The inbreeding coefficient (F_IS) of New Zealand rabbits and Belgian rabbits was higher than that of other rabbits. The neighbour-joining (NJ) tree, principal component analysis (PCA), and population structure analysis of autosomes and Y chromosomes showed that Belgian, New Zealand, Wanzai, Sichuan White, and Minxinan Black rabbits clustered separately, and Fujian Yellow, Yunnan Colourful, and Jiuyishan rabbits clustered together. Wanzai rabbits were clearly separated from other populations (K = 3), which was consistent with the population differentiation index (F_ST) analysis. The selection signature analysis was performed in two populations with contrasting coat colours. With Sichuan White and New Zealand rabbits as the reference populations and Minxinan Black and Wanzai rabbits as the target populations, 408, 454, 418, and 518 genes with a selection signature, respectively, were obtained. Gene Ontology (GO) classification and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis were performed on the genes with a selection signature. The results showed that the genes with a selection signature were enriched in the melanogenesis pathway in all four sets of selection signature analyses.

Our study provides the first insights into the genetics and genomics of Chinese indigenous rabbit breeds and serves as a valuable resource for the further effective utilization of the species.