Identification of important candidate genes in minks with self-biting behaviour using weighted gene coexpression network analysis

Mink self-biting behaviour causes skin damage, reducing fur quality and restricting the development of the mink farming industry. The aim of this study was to investigate the genetic mechanisms underlying self-biting behaviour in minks from a genomic perspective. Using weighted gene coexpression network analysis (WGCNA), we identified functional gene modules and then explored their associations with phenotype, thereby identifying key genes influencing this behaviour. The daily behaviours of minks were analysed through behavioural observation. Gene expression profiles of hippocampi from self-biting and healthy minks (8 males and 10 females in each group) were constructed using transcriptome sequencing. The results revealed significant differences in self-biting, feeding, playing, and lying behaviour between self-biting and healthy minks (P < 0.01). Notably, grooming was significantly correlated with self-biting behaviour (P < 0.05), and slow pace, lying, playing, shaking, and feeding behaviours were strongly correlated with self-biting behaviour (P < 0.01). Differentially expressed genes between self-biting and healthy minks were identified and analysed via WGCNA; then, the correlation coefficient method was used to identify 50 and 20 single genes that may affect mink self-biting in females and males, respectively. Database annotation identified a single gene in the female group, corresponding to Hspa2. This gene is associated with neurological disorders. The Hspa2 gene showed functionally enriched expression under cold and heat stress. Therefore, we speculate that such stress induces abnormal changes in the Hspa2 gene in mink hippocampal tissue, leading to nerve stimulation and neurological disorders, including self-biting behaviour, in mink.