Use of Population Genetics to Assess the Ecology, Evolution, and Population Structure of Coccidioides

摘要

During the past 20 years, a general picture of the genetic diversity and population structure of Coccidioides , the causal agent of coccidioidomycosis (Valley fever), has emerged. The genus consists of 2 genetically diverse species, C. immitis and C. posadasii , each of which contains 1 or more distinct populations with limited gene flow. Genotypic data indicate that C. immitis is divided into 2 subpopulations (central and southern California populations) and C. posadasii is divided into 3 subpopulations (Arizona, Mexico, and Texas/South America populations). However, admixture within and among these populations and the current paucity of environmental isolates limit our understanding of the population genetics of Coccidioides . We assessed population structure of Coccidioides in Arizona by analyzing 495 clinical and environmental isolates. Our findings confirm the population structure as previously described and indicate a finer scale population structure in Arizona. Environmental isolates appear to have higher genetic diversity than isolates from human patients.