Studies On Molecular Marker And δ Differential Display Of Polled Gene In Small-Tail Han Sheep

Small-Tailed Han sheep which is famous for its capacity of producing wool and muttonin China as well as all over the world, is the good female parent of breeding meat sheep inour country. Both ram and ewe of Hebei small-tailed Han sheep are polled, but part ofsmall-tailed Han sheep in Hebei hybridized with that in Shandong,it led to somesmall-tailed Han sheep in Hebei showing horned traits which had brought a lot ofinconvenience in breeding polled-meat sheep and production practices. So molecularmarker technology and δ differential display method were used in this experiment tostudy the horned/polled gene in small-tailed Han sheep,to lay the foundation of breedinghomogyzous polled breeds.PCR-RFLP was used to study the correlation between C/T mutation on one locus ofSYNJ1gene and horned/polled traits of Polled Dorset, small-tailed Han sheep of Hebei andHybrid Mongolian sheep. The result showed that three genotypes TT,CT and CC wereproduced after restriction enzyme Hap Ⅱ digestion. The genotype frequencies’difference was great significant among sheep with different horned/polled trait by using theindependence of Chi-square test (P<0.01). All of these suggested that the SNP on locus361of SYNJ1gene was not associated with horn and poll.In order to further screen the new gene which is related to the polled character insmall-tailed Han sheep, we studied on four RNA pools which respectively belong to theshin tissue of small-tailed Han sheep (horned)、 small-tailed Han sheep of Heibei(polled)、small-tailed Han sheep of Heibei that own horned base as well as polledsmall-tailed Han lamp in this group to study the differential display by using δdifferential display technology. The result showed that110differential segments wereobtained via polyacrylamide gel electrophoresis, in which80segments were obtained bysecond PCR amplification and63differential segments were finally obtained via RT-PCRwhich was used to excluding the false positive. These63segments were submitted intoGenbank, and contrasted with reported sequences in NCBI after analyzing by BLAST,45of those segments which were not found highly homologous sequences in NCBI wereidentified as new expressed segments;12of those segments were similar to the BACsequences in cattle or sheep,and the degree of similarity was generally at least80%, buttheir function had not been known; The analysis results of remaining6segments as followed: the175thsegment was97%similar to the microsatellite DNok281of Caprahicus, but its function have not been known; the180thsegment had the97%similary withthe predicted mRNA of the positiveapolipoprotein B in Ovis aries, the cell recognition andabsorbing LDL are mainly through the identifying apolipoprotein B; the148thsegment was96%similar with predicted mRNA of the elongation factor1-alpha1-like in Ovis aries,and elongation factors mainly promote the polypeptide chain elongation during mRNAtranslation; the segment275-1was shared99%with the clone RP11-279B10(HCIT307A16) complete sequence in chromosome17of Homo sapiens, which function was alsounkown; the195thsegment was shared100%with Homo sapiens synapsin III (SYN3)，The synapsins are a family of neuron specific phosphoproteins associated with themembranes of synaptic vesicles；the50thsegment was100%similar to the predictedmRNA of theUBXN1in Ovis aries and99%similar to the mRNA of UBXN1in BosTaurus, and involved in the ubiquitin-proteasome pathway. δ differential displaysuggested that the gene closely related to polled gene maybe locate in the45newlydiscovered differential segments and that need to be tested further.