Studies On Self-biting Behavior Of Mink And Its Relationship To Correlative Genes

Mink is widely breeded in the part area of China as a main economic animal. The economic value of mink is that its fur is the best raw material of making leather. The self-biting(SB) of mink is a disease which is harm to the farmed minks. Self-biting can influence their growth and development and decrease in pelt-qulity, and then bring out economic expenses for mink production. Up to the present, many researches finded that the development of self-biting was effected by many factors. But the major researches have been focused on the environmental conditions eliciting the SB of minks, but genetic factors have been rarely studied. The purpose of this study is to investigate the possible influence of genetic factors on the self-biting behaviour of minks.Self-biting behaviour as quantitative trait which is affected by both multiple genetic loci and non-genetic factors may be controlled by the possible presence of one or more major genes. In the present study, the dopamine receptor D1(DRD1) gene, dopamine receptor D2(DRD2) gene and 5-hydroxytryptamine 1A receptor gene(5-HT_1AR) were chosen as the candidate genes which affect the self-biting behaviour in minks, through behavioral observed experiment and molecular marker techniques-single strand conformation polymorphism (SSCP), and combined with quantitative genetics method to calculate and deduce the effect of DRD1, DRD2 and 5-HT_1AR genes polymorphism on self-biting behaviours, and discuss the relationship between DRD1, DRD2 and 5-HT_1AR genes and the performance of SB. The following are the results:1. State behaviours are different significantly between SB group and Cotrol group, and in SB group the time of behaviours in nest-box and playing behaviour are shorter than that in Cotrol group, and the time of walking is higher than in Cotrol group. In instantaneous behaviours, the frequency of looking behaviour is different significantly between two groups.2. The genomic sequences of mink DRD1 gene were cloned; the length of whole sequences is 931bp. It had been released to GenBank(Accession No. EF249297). One SNP was found in DRD1 gene, that is T179C. The AA, AB and BB genotypes were deceted. Results of association analysis between the SNPs of DRD1 gene and self-biting behaviour of mink showed that, this SNP have a relationship with self-biting behaviour (P<0.05).3. The partial genomic sequences of mink DRD2 gene were cloned, including exon 2, exon 3, intron 2, exon 4, exon 5 and intron 4. the length of exon 2, exon 3 and intron 2 sequences is 1267bp, and the length of exon 4, exon 5 and intron 4 sequences is 1048bp. They had been released to GenBank(Accession No. EF249299 and EU085471).4. Six SNPs were found in DRD2 gene. The SSCP polymorphism was not detected in exon 2, exon 3 and exon 5. The SSCP polymorphism in intron 2 have a relationship with self-biting behaviour (P<0.05), and the insert of bases could easily result in self-biting. The polymorphisms of the exon 3 (A95G) and intron 4 (A602G) had a distinguished tendency to self-biting behaviour of mink (P<0.2).5. The partial genomic sequences of mink 5-HT_1AR gene were cloned; the length of whole sequences is 904bp. It had been released to GenBank (Accession No. EF249298). Three SNPs were found in 5-HT_1AR gene of mink, only the polymorphisms of C287G had a distinguished tendency to self-biting behaviour of mink (P<0.2).