title: Coccidioides species determination: does sequence analysis agree with restriction fragment length polymorphism?
abstract: Fifteen Coccidioides isolates were previously examined for genetic diversity using restriction fragment length polymorphism (RFLP); two fragment patterns were observed. Two isolates demonstrated one banding pattern (designated RFLP group I), while the remaining 13 isolates demonstrated a second pattern (designated RFLP group II). Recently, molecular studies supported the division of the genera Coccidioides into two species: Coccidioides posadasii and Coccidioides immitis. It has been assumed that the species division corresponds to the RFLP grouping. We tested this hypothesis by amplifying the ribosomal DNA internal transcribed spacer region as well as the dioxygenase, serine proteinase, and urease genes from 13 isolates previously examined by RFLP and then sequencing the PCR products. The appropriate species for each isolate was assigned using phylogenetically informative sites. The RFLP grouping agreed with the Coccidioides species assignment for all but one isolate, which may represent a hybrid. In addition, polymorphic sites among the four genes examined were in agreement for species assignment such that analysis of a single gene may be sufficient for species assignment.
authors.affiliation: Department of Medical Microbiology and Immunology, School of Medicine, University of California, Davis, CA, 95616, USA, smjohnson@ucdavis.edu.
authors.forename: Suzanne M
authors.initials: SM
authors.lastname: Johnson
authors.forename: Erin L
authors.initials: EL
authors.lastname: Carlson
authors.forename: Demosthenes
authors.initials: D
authors.lastname: Pappagianis
mesh_terms: D003045:Coccidioides / Q000145:classification* / Q000235:genetics*; D003047:Coccidioidomycosis / Q000175:diagnosis; D004271:DNA, Fungal / Q000737:chemistry / Q000235:genetics; D021903:DNA, Ribosomal Spacer / Q000737:chemistry / Q000235:genetics; D006801:Humans; D008828:Microbiological Techniques / Q000379:methods*; D025202:Molecular Diagnostic Techniques / Q000379:methods*; D012150:Polymorphism, Restriction Fragment Length; D017422:Sequence Analysis, DNA / Q000379:methods*; D014510:Urease / Q000235:genetics
chemical_list: D004271:DNA, Fungal; D021903:DNA, Ribosomal Spacer; D014510:Urease