Jinghai Yellow Chicken Igf-i Gene Polymorphism And Production Performance Of Its Genetic Law

With chicken IGF-I gene as a candidate gene, we carried out DNA sequencing, PCR-SSCP and PCR-RFLP techniques to analyze nucleotide variation in 5'UTR and the effect on growth characteristics of Jinghai yellow chicken. We studied inheritance of gene we found in three continuous generation of Jinghai yellow chicken to indicate the relationship between gene polymorphism and growth traits, tap new gene important for economic traint. We investigate the effect of artificial breeding on transmission of IGF-I gene between generations. The process of improvement of economic traits and new breed would be accelerated by marker-assisted selection(MAS). In this study, we researched the effect of IGF-I gene economic traits to provide new efficient genetic for chicken MAS. The results as follows:We studied nucleotide variation in 5'UTR by sequencing, PCR-SSCP and PCR-RFLP technique and found eight polymorphic loci. Seven of them were SNP, the other was an insertion of GAAAA. All of SNPs were gene conversion, five of them were G to A, one was A to C, one was C to T. According to their location, We named them G49754A, G49778A, G49824A, A49944C, G49961A, G50034A, DelGAAAA50077 and C50180T .G49754A, G49778A and G50034A led to the mutations of restriction enzyme cutting site Tru1 I ,Tai I and Pst I respectively. We found that Pst I was the right one found by Nagaraja。The results of Tru1 I and Tai I and SSCP indicated that G49754A and G49778A were completely linked., G49754A and G49778A were regarded as one site called G49754A/G49778A.We found DelGAAAA50077 N allele always accompanied with G50034A A allele after Pst I restriction enzyme. It shows that G50034A A allele would link with DelGAAAA50077 N allele in Beijing Yellow Chicken. G49754A/G49778A, G50034A and DelGAAAA50077 in Jinghai yellow chicken, Youxi Partridge, and AA chicken were studied. We didn't find mutation of AA chicken on genotype distribution. Most of genotype on G49754A/G49778A and G50034A of sites in Jinghai yellow chicken, Youxi Partridge were heterozygous. DelGAAAA50077 only detected in Jinghai yellow chicke.The resoults of linkage disequilibrium analysis showed that G49754A and G49778A were perfect linkage disequilibrium in Jinghai yellow chicken. The linkage disequilibrium between G50034A and DelGAAAA50077 was strong than that of G49754A/G49778A and G50034A . The linkage disequilibrium between G49754A/G49778A and DelGAAAA50077 was weak.In the theory, there were eight haplotype on in G49754A/G49778A, G50034A and DelGAAAA50077 in Jinghai yellow chicken . We detected only four effective haplotypes (P> 0.03) ,which oritented AAGN, GGAN haplotype.We studied correlation between G49754A/G49778A, G50034A and, DelGAAAA50077 and laying traits respectively. The results showed that G49754A/G49778A,G50034A and DelGAAAA50077 didn't affect 300 day-old egg number number and average egg weight significantly(P > 0.05).Through correlation analysis , we found that G49754A/G49778A affected birth weight significantlyt, but no effect on the weight after the 4,8 weeks. The weight of AA/AA genotype after 12,16 weeks and 300 days were heavier than that of other genotype. It indicated that A/A allele may be preponderant for weight after 12 weeks. G50034A didn't affect birth weight and weight after 4,8 weeks . The weight of GG genotype after 12,16 weeks and 300 days were heavier than that of other genotype. It indicated tha GG allele was the dominant for weight after 12 weeks. The birth weight, 4,8,12,16 week and 300 days weigh of DD types on DelGAAAA50077 were lighter than that of NN and ND types . We researched the inheritance of G49754A/G49778A, G50034A, DelGAAAA50077, InsAA56493 and G95852A (the last two was found by others) between three generations.It showed that genotype frequency on G49754A/G49778A, G50034A and G95852A changed regularly. The frequency AA/AA type on G49754A/G49778A changed from 0.234 in7 generation to 0.393 in 9 generations, frequency of A/A allele increased from 0.493 in 7 generation to 0.628 in 9 generation. The frequency AA type on G50034A changed from 0.291 in 7 generation to 0.325 in 9 generations, frequency of A allele increased from 0.541 in 7 generation to 0.573 in 9 generation. The frequency of GG type on G95852A changed from 0.110 to 0.308, and G allele frequency changed from 0.344 to 0.547 .The results of test for independence showed that genotype distribution of G49754A/G49778A, InsAA56493 and G95852A were not independent between three generations. Their genotype distribution were related with generation, whereas DelGAAAA50077 were not related with the generation.Genetic polymorphism index indicated that G49754A/G49778A, G50034A and G95852A changed regularly, whereas DelGAAAA50077 and InsAA56493 did not.