Studies On Chromosome Karyotype And Blood Protein Polymorphism In Vc-Rex Rabbits

The chromosome karyotype of the Vc- I and Vc- II Rex rabbits was studied by using conventional cytogenetics technique. The chromosome preparation was made from leukacoytes cultured from peripheral blood. The results showed as follows: The diploid chromosome number of Vc-Rex rabbit was 2n=44,21pairs of autosomes and one pair of sex chromosomes. The autosomes were divided into 4 groups according to their relative length, arm ratio and centromere index of each chromosome, and the No. 1~No.8 of group A were metacentric chromosomes(M); the No.9~No.ll of group B were subnetacentric chromosomes(SM); the No.12~No.17 of group C were subtelocentric chromosomes(ST); the No.l8~21 were telocentric chromosomes(T). The X chromosome was submetacentric and the Y chromosome was telocentric. The chromosome karyotype of male rabbit was 44,XY. The G-banding patterns were described and there was no significant difference between two strains of Rex rabbit in G-banding patterns.Five protein loci, including erythrocyte esterase(Es-l,Es-2 and Es-3), pretransferrin(Prt), postalbumin(Po), were detected by using vertical plate polyacrylamide gels(PAGE) electrophoresis in blood samples from Vc- I Rex rabbit(Vc- I ), Vc- II Rex rabbit(Vc- II), Japanese white rabbit(JWR), New Zealand white rabbit(NZR). Gene frequencies and genetic distance among the four rabbit breeds (or strains) were calculated and the cluster analysis was conducted by using unweighted pair-group arithmetic mean. There were 3 phenotypes in Es-1, Es-2 ,Es-3 and Po, which were controlled by 2 autosomal codominant alleles; 6 phenotypes in Pit controlled by 3 autosomal codominant alleles. The frequency of gene and phenotype of the polymorphic protein loci analyzed were different among 4 rabbit colonies. The average heterogosity was 0.4874(Vc- I ),0.4770(Vc-II),0.4648(JWR),0.4743(NZR), respectively. According to the cluster analysis, the relationship between Vc-1 and Veil was the nearest; Vc- 1 and Vc- II were nearer to JWR than to NZR; The relationship between JWR and NZW was the farthest. And it was consist with the history of breeding. It is practicable to differentiate rabbit breeds and strains and to probe the relationship of rabbits through protein polymorphism.