Studies On Polymorphisms Analysis In Exon2 Of DQA1,DQB1,DQA2 Gene And Their Relationship With Nematode Resistance And Immune Traits

MHC is a chromosomal region consisting of a group of closely linked loci which are highly polymorphic and play a central role in the immune system.So it is a candidate gene in disease resistance breeding. PCR-SSCP/PCR-RFLP were used to analyze the polymorphisms of exon 2 of DQA1,DQA2,DQB1 gene in Laiwu black goats, Lubo goats and Boer goats.The effects ofgenotypes of exon 2 of DQB1,DQA2 gene on nematode resistance ,immune traits were estimated.The results were as followed:1. Polymorphisms of exon 2 of DQA1 was analyzed by PCR-SSCP , Eight genotypes were detected.and Its homozygous were sequenced, 23 polymorphic sites were detected .2. The exon 2 of DQA1gene were amplified by PCR respectively. DNA sequences are compared. Comparative analysis showed that the homologies of DQA1 gene among Human, Bovine, sheep, goats, Laiwu black goats are very high.3. PCR-RFLP was used to analyze the polymorphisms of exon 2 of DQA2 ,DQB1 gene in Laiwu black goats,Lubo goats and Boer goats.it was showed four DQA2 gene exon 2 genotypes and seven DQB1 gene exon 2 genotypes by analyzing restriction map and sequencing. Polymorphic sites were detected at base position 77, 79,80,169 of exon 2 of DQA2 gene. 24,151 of exon 2 of DQB1 gene.4. The association of polymorphisms of exon 2 of DQA2, DQB1 gene with nematode resistance in three goat breeds was analyzed by SAS 8.0 software GLM program, In DQB1 gene, the nematode eggs count of genotype BC, DD was significantly lower than that with genotype BB (P <0.05). by analysising in the breeds , we found that in Lubo goats, the nematode eggs count with genotype BC was significantly lower than that with genotype AC (P <0.05). other genotypes and nematode eggs count had some relevance, but did not reach significant levels (P> 0.05).5. The association of polymorphisms of exon 2 of DQA2 , DQB1 gene with immune traits in three goats was analyzed by SAS 8.0 software GLM program. The results suggested that for DQA2 gene, RBC in Laiwu black goats with genotype AB was lower than that with genotype BB,BC(P>0.05), MCH in Laiwu black goats with genotype AB was higher than that with genotype BB, BC(P>0.05);W-LCR in Laiwu black goats with genotype BC was higher than that with genotype AB,BB(P>0.05);W-SCC in Laiwu black goats with genotype BC was lower than that with genotype AB, BB(P>0.05). RBC in Lubo goats with genotype AB was significantly higher than that with genotype BB (P<0.05), RBC in Lubo goats with genotype AB was higher than that with genotype BC(P>0.05). WBC in Lubo goats with genotype AB was significantly higher than that with genotype AC (P<0.05). WBC in Lubo goats with genotype AB was higher than that with genotype BB(P>0.05).HCT in Lubo goats with genotype AB was significantly higher than that with genotype BB ,BC (P<0.05).W-LCR in Lubo goats with genotype BC was significantly higher than that with genotype BB (P<0.05). W-LCR in Lubo goats with genotype BC was higher than that with genotype AC(P>0.05). for DQB1 gene,W-SCR in Laiwu black goats with genotype BC was significantly higher than that with genotype AC and CC (P<0.05), W-LCR in Laiwu black goats with genotype BC was significantly lower than that with genotype CC (P<0.05); W-LCC in Laiwu black goats with genotype BC was lower than that with genotype AC, CC (P>0.05). W-LCC in Boer goats with genotype BC was lower than that with genotype AA , AB (P>0.05) ; W-LCC in Lubo goats with genotype BC and AC was significantly lower than that with genotype AA (P<0.05).These results may be applied to marker assisted selection in disease resistance breeding of goats.