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Phylogenetic Analysis and the Evolution of the 18S rRNA Gene Typing System of Acanthamoeba
Author(s) -
Fuerst Paul A.,
Booton Gregory C.,
Crary Monica
Publication year - 2015
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/jeu.12186
Subject(s) - biology , acanthamoeba , phylogenetic tree , 18s ribosomal rna , typing , dna sequencing , gene , ribosomal rna , genetics , ribosomal dna , evolutionary biology , sequence (biology) , phylogenetics , sequence analysis , computational biology
Abstract Species of Acanthamoeba were first described using morphological characters including cyst structure and cytology of nuclear division. More than 20 nominal species were proposed using these methods. Morphology, especially cyst shape and size, has proven to be plastic and dependent upon culture conditions. The DNA sequence of the nuclear small‐subunit (18S) rRNA, the Rns gene, has become the most widely accepted method for rapid diagnosis and classification of Acanthamoeba . The Byers–Fuerst lab first proposed an Rns typing system in 1996. Subsequent refinements, with an increasing DNA database and analysis of diagnostic fragments within the gene, have become widely accepted by the Acanthamoeba research community. The development of the typing system, including its current state of implementation is illustrated by three cases: (i) the division between sequence types T13 and T16; (ii) the diversity within sequence supertype T2/T6, and (iii) verification of a new sequence type, designated T20. Molecular studies make clear the disconnection between phylogenetic relatedness and species names, as applied for the genus Acanthamoeba . Future reconciliation of genetic types with species names must become a priority, but the possible shortcomings of the use of a single gene when reconstructing the evolutionary history of the acanthamoebidae must also be resolved.