IGS基因及RAPD标记分析在加特隐球酵母基因分类中的应用

根据ITS1-5.8S-ITS2区域的特异核酸序列变化,加特隐球酵母Cryptococcus gattii(≡新型隐球酵母加特变种Cryptococcu neoformans var.gattii)可分为6种基因型。本研究通过检测加特隐球酵母的IGS基因,发现其IGS序列有着更丰富的变异和信息位点。通过结合加特隐球酵母RAPD(随机扩增的多态性DNA)图谱比较研究,与IGS和ITS的序列分析结果大体一致,说明新近发现的加特隐球酵母ITS8型确实有别于以前报道过的其他加特隐球酵母ITS基因型。研究证明IGS1及IGS2基因片段分析可以作为加特隐球酵母基因分类鉴定中有效的辅助鉴别的分子生物学方法,联合多种基因分类鉴定的方法可以更有效地揭示新型隐球酵母加特变种种内不同基因亚型间的遗传进化关系。

Genotype differentiation of Cryptococcus gattii based on IGS sequence and RAPD analyses

Based on sequence variations in the ITS1-5.8S-ITS2 region, Cryptococcus gattii (≡ Cryptococcu neoformans var. gattii) strains were classified into six genotypes. In this study, more sequence variations were revealed in the intergenie spacers (IGS) of rDNA among strains of this species. The C. gattii strains with different ITS and IGS types were also distinguished by RAPD (random amplified polymorphie DNA) analysis using three primers. The RAPD pattern similarities or differences among the C. gattii strains studied were roughly consistent with their relationships depicted in IGS sequence analysis. A recently reported new ITS genotype of C. gattii (ITS type 8) was also differentiated from all other heretofore reported ITS types of the species by RAPD band pattern and IGS sequence analyses. The results of this study suggest that IGSI and IGS2 nucleotide sequences are suitable for genotype differentiation of C. gattii, and that the combination of ITS, IGS1 and IGS2 region sequence analyses are more discriminative for strain differentiation of the species.