The Identification And Their SNPs Of Differential EST In Small Intestine Of Different Pig-types

Pig’s small intestine is the important place of nutrient digestion and absorption,and shows specificity between two pig-types, Chinese native and introduced pigbreeds. Researching the differential expression of genes in small intestine tissuebetween two pig-types is conducive to understanding of the genetic mechanism aboutthe nutrients utilization.125pigs with body weight85kg from Anhui native breeds(Dingyuan, Wannanhua and Wannan black) and77pigs with body weight100kgfrom LLD (Large White×Landrace×Duroc) were selected, and slaughtered for thesamples of pig small intestine tissue. The mRNAs extracted from the intestinal tissuesof all pigs were reversely transcribed into cDNA.18primer pairs combinated by threeanchor primers and six random primers were employed for differential display ofreverse transcriptional polymerase chain reaction (DDRT-PCR). Differencial ESTswere identified using PCR and sequencing. The linkage group of EST was estimated,and the SNPs of ESTs and their association with the pig-types were analyzed. Theresults showed that:1. There were180ESTs, including6inter-individual differential ESTs in thenative pig breeds,12inter-individual differential ESTs in LLD, and8differentialESTs between the native breeds and LLD. Three ESTs (G24-300、G01-360andA12-340) were selected from differential ESTs. The expression level of G24-300inthe LLD was higher than that in local pigs, while the expression levels of G01-360and A12-340EST didn’t differ between two pig-types. G24-300located inchromosome2and linked with serum response factor binding protein1gene(SRFBP1), ferritin mitochondrial gene (FTMT) and lysyl oxidase gene (LOX) to formFTMT-G24-SRFBP1-LOX. G01-360was located in chromosome13and it linkedwith olfactory receptor5K1-and3-like genes.2. The homologous sequence of G24-300in pig genome was not found, whilethere were many sequences that homologed with G01-360over80%and distributedin whole genome of pig, in which the homologous of three fragments were99%,98%and98%, respectively. There was consensus sequence of27bp in G01-360andhomologous sequences, which showed that the27bp sequence might be highconserved domains. 3. The polymorphism in G24-300was detected. Eight SNP sites, T30C, A117G,C149T, A157C, A161T, G273T, G282T and T294C, were found in the G01-360. InA117G and A161T,117AA was with161AA, and117AG with161AT. It implied thatA117G and A161T might be related SNP sites. The genotype frequencies of149TTand149CC were lower in Wannan black, Wannanhua and Dingyuan pig, low than0.062, while there were higher genotype frequencies in LLD,0.2567and0.2078. Theallele frequency distribution between two pig-types was significantly different(P<0.05). The genotype frequencies at T149C, A157C and T273G differedsignificantly between two pig-types, but didn’t differ among local pig breeds.