Preliminary Study On GTA9 Locus Of M.leprae In Sichuan

Objective:To understand the genotype characteristic and the geographic distribution of GTA9 locus of fifty-six M.leprae cases collected from Sichuan . Methods:We choose the skin biopsies of the people affected by leprosy ,which were come from the institute of dermatology and venereology, Sichuan provincial People′Hospital in 2006～2008.Some specimens were used in this research which thickness or diameter of skin were less than 0.5cm and has lesser adipose tissue. 30 skin biopsies from liangshan prefecture,5 skin biopsies from ganzi prefecture and 21 from other parts of Sichuan province were studied.All cases were diagnosed by experienced pathology physician. DNA extracted from skin biopsies of patients with leprosy was subjected to PCR followed by 2℅ agarose gelanalysis and DNA sequencing to determine the number of repeat.The primer was synthesized which designed by Korea scholar.The PCR amplification reaction was transited three steps,including pre-denaturlization,forty circulations of heat and extence.Each experiment was supposed three comparisions:blank comparision,negative comparision and quality control comparision. The DNA sequences of the PCR products were analysed by the dideoxy chain termination method of Sanger and software Chromas. unvariate analyse was used with SAS version 9.13. Results: The study shows the expression of GTA9 locus of 56 leprae bacillus is 93.5 percents,there is diversity in the number of allele copies,which changed from 8 to 50.In all positive cases,the positive rate is 15.7% in 15 copies,11.8% in 19 copies and 9.8% in 21 copies.Only Liangshan prefecture has 14,20,30 copies and which more than 33.Copies of GTA9 locus in other parts of Sichuan province are all less than 33.There are 13 kinds of GTA9 locus allele in liangshan prefecture and 8 kinds in it.The number of samples in Sichuan is more than 40,it is not be thought that there is regional difference between the liangshan prefecture and other parts of Sichuan province by chi-square test( X2=0.27,P>0.05). They were analysed by statistics,which are allele copies of M.Leprae and geographic distribution of Sichuan province.The copies were divided to three sections: 8～18,19～29,30～53.It was counted by H Test.H is 98.17,there is difference in copies of these three sections(P<0.05).and after adjustment Hc is 116.87 because of much same ranks,which were submitted approximatly chi-square distribution which v is 2(P<0.005). It is not be thought that there is difference of copies of GTA9 locus in sichuan province. Conclusion: 1.There is high positive expression in M.Leprae GTA9 in Sichuan.2.There is obvious diversity in M.Leprae GTA9 in Sichuan. 3.There is no distinct connection between the copies of M.Leprae GTA9 and geograhic distribution in Sichuan.4.The allele locus of repeat copies more than 33 may be considered for one of typical differences between liangshan prefecture and other parts of Sichuan and is likely to supplies consignment for futher epidemiological study.