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huojinlong9287(金币+100, 翻译EPI+1): 2010-11-14 15:30:42
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In 1980, BMI was exploited by ***University based on the small-ear pigs at Xishuangbanna, Yunnan Province. A pair of progenitors was a sow and her sons. Previously, the propagation was conducted by means of highly full-sib or parent-offspring inbreeding and each generations underwent the strict selection. As heterozygotic genes were separated and recombined in the process of inbreeding, BMI has already owned six families and eighteen substrains with different phenotypes and genotypes. With the development of inbreeding and generating, the white with colored descendants were generated although the progenitors of BMI were both black phenotype. Namely, BMI was divided into the black and white with mixed-color phenotypes in light of the coat color . According to the coat color difference of the mated individuals, there are three cases. In the 1st case, uniform black coat or black along with white with mixed-color descendants are generated by mating of the two black phenotype pigs. In the 2nd case, the similar results to that of the above come out with mating between the black and white with the mixed color pigs. In the 3th case, the descendants own the same coat color as their white with the mixed color parents. As it is well known, the coat color genetic process of most mammals is closely related to MC1R gene in E locus and the dominant alleles at E locus often lead to the generation of all black individuals. Therefore, it was deduced that the black phenotype was dominant as compared with the white phenotype with colored. If the E position was supposed to be controlled by a pair of EBMI/Ebmi allelic genes in BMI, the black could possess EBMI/EBMI or EBMI/Ebmi genotypes and the colored should own the Ebmi/Ebmi genotype. Up to now, it is unclear about the molecular mechanism of domination relation between EBMI and Ebmi genes. As the genetic background and pedigree of BMI is well learned, MC1R gene was used as the main candidate genes of the research for the coat genetic process and the related mechanism was investigated by molecular bio-methods, the direct sequencing of PCR products and cloning sequencing of MC1R gene with the individuals of EBMI/EBMI, EBMI/Ebm and Ebmi/Ebmi genotype. |
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