Data from: Comparative analyses of clinical and environmental populations of Cryptococcus neoformans in Botswana

Cryptococcus neoformans var. grubii (Cng) is the most common cause of
fungal meningitis, and its prevalence is highest in sub-Saharan Africa.
Patients become infected by inhaling airborne spores or desiccated yeast
cells from the environment, where the fungus thrives in avian droppings,
trees and soil. To investigate the prevalence and population structure of
Cng in southern Africa, we analysed isolates from 77 environmental samples
and 64 patients. We detected significant genetic diversity among isolates
and strong evidence of geographic structure at the local level. High
proportions of isolates with the rare MATa allele were observed in both
clinical and environmental isolates; however, the mating-type alleles were
unevenly distributed among different subpopulations. Nearly equal
proportions of the MATa and MATα mating types were observed among all
clinical isolates and in one environmental subpopulation from the eastern
part of Botswana. As previously reported, there was evidence of both
clonality and recombination in different geographic areas. These results
provide a foundation for subsequent genomewide association studies to
identify genes and genotypes linked to pathogenicity in humans.

格特隐球菌格鲁比变种（Cryptococcus neoformans var. grubii, 下称Cng）是引发真菌性脑膜炎最常见的病原体，其流行率在撒哈拉以南非洲地区最高。人类可通过吸入环境中的空气传播孢子或干燥酵母细胞而感染该真菌，该真菌可在鸟类粪便、树木及土壤中存活繁衍。为探究南部非洲地区Cng的流行情况与种群结构，本研究对77份环境样本及64例患者的真菌分离株进行了分析。研究检测到分离株间存在显著的遗传多样性，且在局部尺度上存在强烈的地理结构证据。临床与环境分离株中，携带罕见MATa交配型等位基因的分离株占比均较高；但不同亚群间的交配型等位基因分布并不均衡。在全部临床分离株以及博茨瓦纳东部的一个环境亚群中，MATa与MATα交配型的占比几乎相当。正如既往研究报道，不同地理区域均存在克隆性繁殖与基因重组的证据。本研究结果为后续开展全基因组关联研究以鉴定与人类致病性相关的基因及基因型奠定了基础。