Studies On DNA Markering And Screening Differential Expression Of Polled Character In Small Tail Han-sheep

There are so many advantage of breeding polled sheep. they are difficult of destroy the fencing,In the same barn it could contain more polled ovine than horn sheep, decrease nutritive material consume that supply to horn, meanwhile decrease the damage of horn fighting.The polled sheep is more manage than the horn sheep. A excellent breed named polled Drost had been breeded in Australia. Currently breed polled sheep became a trend of development.So breeding polled sheep is very significance for stockbreeding development. This experiment aims at searching genes associated with sheep horn through molecular biology method, in order to provide theoretical basis for breeding polled sheep.The results was showed as follows.1.The research of microsatellite: In order to carry out PCR and detect PCR production of microsatellite AGLA226, this experiment use Small Tail Han-sheep, Polled Dorst and hybrid Mongolia sheep that are different horn types as samples. Experiment found eight allelic genes(A:190bp,B:166bp,C:184bp,D:160bp,E:180bp,F:156bp,G:175bp,H:152bp)and 4 genotypes(AB,CD,EF,GH)in all.They were analized by SPSS software about independence Chi-square test. The results indicated that types of horns has indistinctive associativity difference with microsatellite AGLA226(P>0.05).2. Analysis of SNPs:This experiment use DNA of 3 cattle species(horn Hesitate cattle, polled Angus cattle and polled Hereford cow)and Small Tail Han-sheep, Polled Dorst and hybrid Mongolia sheep that are different horn as samples,used the primer of cattle SYNJ1 gene .Then adopt the PCR-SSCP and PCR sequence to analyze SYNJ1 gene. The results indicated that there was no SNP related to horn trait and no polymorphism was found on the locus of SNP bSYNJ1_C3981T. Only a C-T nucleotide difference was found between cattle and sheep.3,The research of DDRT-PCR: we extracted RNA from 3 horned sheep and 3 polled sheep skin tissue respectively,and composed horned RNA pool and polled RNA pool according to the Phenotype of the sheep. Horned sheep RNA pool and polled sheep RNA pool were reverse transcripted to 2 kinds of cDNA,then carried out DDRT-PCR. The production of DDRT-PCR was analyzed and 30 differential expression gene fragments were screening. After reject false positive fragments Through the second PCR amplification, clone and sequence, only 7 fragments were remained.We designed 7 primers according to the sequenced results of 7 framents respectively, selected cDNA which were reverse transcripted as template and carried out PCR to reject the false positive fragments again.At last, we gained 1 differential fragment which named S1-162. In Genbank, compared this fragment with mRNA (1687-1842bp,UTR)of keratin83 in sheep and mRNA (1690-1835bp, UTR) of keratin83 Bos Taurus, we found 100% and 93% homology respectively from analysis.We carried out bioinformatics analysis for its amino acid. Through the analysis, we found that it can form heterodimers that are organised into tetramers and has a coiled coil structure.So we make a hypothesis that it may be had a regulatory functions for the horn exist or not.the gene maybe a upper reaches controlling gene ,but the specific mechanism need a deep research in the future.