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Biogeographic range expansion into South America by Coccidioides immitis mirrors New World patterns of human migration

Authors :
Fisher, Matthew C.
Koenig, Gina L.
White, Thomas J.
San-Blas, Gioconda
Negroni, Ricardo
Alvarez, Isidro Gutierrez
Wanke, Bodo
Taylor, John W.
Source :
Proceedings of the National Academy of Sciences of the United States. April 10, 2001, Vol. 98 Issue 8, 4558
Publication Year :
2001

Abstract

Long-distance population dispersal leaves its characteristic signature in genomes, namely, reduced diversity and increased linkage between genetic markers. This signature enables historical patterns of range expansion to be traced. Herein, we use microsatellite loci from the human pathogen Coccidioides immitis to show that genetic diversity in this fungus is geographically partitioned throughout North America. In contrast, analyses of South American C. immitis show that this population is genetically depauperate and was founded from a single North American population centered in Texas. Variances of allele distributions show that South American C. immitis have undergone rapid population growth, consistent with an epidemic increase in postcolonization population size. Herein, we estimate the introduction into South America to have occurred within the last 9,000-140,000 years. This range increase parallels that of Homo sapiens. Because of known associations between Amerindians and this fungus, we suggest that the colonization of South America by C. immitis represents a relatively recent and rapid codispersal of a host and its pathogen.

Details

ISSN :
00278424
Volume :
98
Issue :
8
Database :
Gale General OneFile
Journal :
Proceedings of the National Academy of Sciences of the United States
Publication Type :
Academic Journal
Accession number :
edsgcl.74802570