Study On The Polymorphism Of PIT-1 Gene And Genetic Diversity Of Mink

Mink is small precious fur-bearing animal, and the furs of mink, fox, and persian lamb are already the three key products in the international fur market. Now the mink industry is facing good development opportunity and prosect, so improving the growth performance of mink will bring more economic benefits to the mink industry.The minks bred in Dalian Jinzhou base were chosen as our research object, the SNPs in the coding regions of the PIT-1 were studied by cloning and sequencing combined with PCR-SSCP technique, finally, the correlation between polymorphism caused by growth traits was analyzed. This study made foundation of marker assisted selection using marker genes related growth performance, and provided way to breed mink, improve growth rate, fur quality of mink at molecular level, five species which were standard-pitchy mink, black mink, sapphire mink, brown mink, white mink were collected in this research, and applied ISSR marker to analyzing their genetic relationship. Main research results as follows:1. The sequence (117bp) of the exon1 in PIT-1 gene, whose homology with Equus caballus PIT-1 gene exon1 was 90%,and the homology with Canis lupus, Ovis aries, Bos taurus ,Homo sapiens were achieve to 88% through Blast of NCBI, was cloned and submit to the genebank. The sequence was conserved in mammal animals. There no SNPs in this sequence by SSCP.2. The sequence (150bp) of the exon4 in PIT-1 gene was cloned and the accession number was GU362205. A SNP in the exon4 was detected in the research by SSCP, the least square analysis showed that the genotypes of mutation had significant association with Body Weight (BW), Chest Circumference (CC), Abdomen Circumference (AC) (P<0.01), AA genotype mink had a significant higher Body Weight (BW), Chest Circumference (CC), Abdomen Circumference (AC) than BB genotype mink in the whole mink group. AA genotype were the beneficial genotype for the Body Weight (BW), Chest Circumference (CC), Abdomen Circumference (AC) in mink.3. The sequence (164bp) of the exon6 in PIT-1 gene was cloned and the accession number was GU446673. A SNP in the exon 6 was detected in the research by SSCP, the least square analysis showed that the genotypes of mutation had significant association with Body Weight (BW), Body Longth (BL), Body Height (BH), Chest Circumference (CC), Abdomen Circumference (AC) and Carcass Weight (CW) in the whole mink group (P<0.01). DD genotype mink had a significant higher Body Weight (BW), Body Longth (BL), Chest Circumference (CC), Abdomen Circumference (AC) than CC genotype mink in the whole mink group.4. The interaction of C43T mutation and A143G mutation in PIT-1 gene was discussed through combination genotype analysis, the least square analysis showed that the combined genotype had significant association with Body Weight (BW), Chest Circumference (CC), Abdomen Circumference (AC) and Carcass Weight (CW) in the whole mink group. Results of multiple comparison revealed that AADD genotype minks had a higher Body Weight (BW), Chest Circumference (CC) and Carcass Weight (CW) than AABB genotype minks; BBDD genotype minks had a higher Body Longth (BL) the other genotypes minks.5. In ISSR molecular marker analysis , Polymorphic bands percent , Shannon's Information index, Nei's (1973) gene diversity showed high genetic diversity. Nei's genetic distance was used to analyze five populations, the results showed that the genetic distance between sapphire mink and brown mink was the nearest among the populations, and the genetic distance between standard-pitchy mink and sapphire mink was the longest. The coefficient of gene differentiation were used to analyze population genetic differentiation and the results showed that the genetic differentiation degree between populations was lower and the hereditary variation primarily came from within population.