Burt A, Dechairo B M, Koenig G L, Carter D A, White T J, Taylor J W
Department of Plant Biology, University of California, Berkeley 94720, USA.
Mol Ecol. 1997 Aug;6(8):781-6. doi: 10.1046/j.1365-294x.1997.00245.x.
Coccidioides immitis causes coccidioidomycosis, a fungal disease of both immuno-compromised and otherwise healthy people; it is capable of causing large epidemics and the disease is often refractory to chemotherapy. To quantify the magnitude of population differentiation and estimate levels of gene flow in C. immitis, multilocus genotypes were scored for 20-25 clinical isolates from each of Bakersfield (California), Tucson (Arizona), and San Antonio (Texas). The molecular markers used were PCR products with polymorphic restriction endonuclease sites, found and characterized in a previous study of the Tucson population. The data show very highly significant differences in allele frequencies between all three populations, and suggest very low levels of migration between populations. One isolate in the San Antonio sample was an outlier, showing the California-specific allele at all four of the loci distinguishing the two populations, and subsequent inquiries indicated that the infection had indeed been acquired in California. Thus, genetic information can be used to infer the geographical origin of a fungal infection.
粗球孢子菌可引发球孢子菌病，这是一种在免疫功能低下者和其他健康人群中均可发生的真菌病；它能够引发大规模的流行，且该疾病往往对化疗具有抗性。为了量化粗球孢子菌群体分化的程度并估计其基因流动水平，对来自加利福尼亚州贝克斯菲尔德、亚利桑那州图森和得克萨斯州圣安东尼奥的20 - 25株临床分离株进行了多位点基因型分析。所使用的分子标记是具有多态性限制性内切酶位点的PCR产物，这些位点是在先前对图森群体的研究中发现并鉴定的。数据显示，所有三个群体之间的等位基因频率存在非常显著的差异，并表明群体之间的迁移水平非常低。圣安东尼奥样本中的一个分离株是一个异常值，在区分这两个群体的所有四个位点上都显示出加利福尼亚特有的等位基因，随后的调查表明该感染确实是在加利福尼亚获得的。因此，遗传信息可用于推断真菌感染的地理来源。
