title: Molecular phylogeny and evolutionary relationships of Cryptosporidium parasites at the actin locus.
abstract: To further validate previous observations in the taxonomy of Cryptosporidium parasites, the phylogenetic relationship was analyzed among various Cryptosporidium parasites at the actin locus. Nucleotide sequences of the actin gene were obtained from 9 putative Cryptosporidium species (C. parvum, C. andersoni, C. baileyi, C. felis, C. meleagridis, C. muris, C. saurophilum, C. serpentis, and C. wrairi) and various C. parvum genotypes. After multiple alignment of the obtained actin sequences, genetic distances were measured, and phylogenetic trees were constructed. Results of the analysis confirmed the presence of genetically distinct species within Cryptosporidium and various distinct genotypes within C. parvum. The phylogenetic tree constructed on the basis of the actin sequences was largely in agreement with previous results based on small subunit rRNA, 70-kDa heat shock protein, and Cryptosporidium oocyst wall protein genes. The Cryptosporidium species formed 2 major clades; isolates of C. andersoni, C. muris, and C. serpentis formed the first major group, whereas isolates of all other species, as well as various C. parvum genotypes, formed the second major group. Intragenotype variations were low or absent at this locus.
authors.affiliation: Division of Parasitic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, U.S. Department of Health and Human Services, Atlanta, Georgia 30341, USA.
authors.forename: Irshad M
authors.initials: IM
authors.lastname: Sulaiman
authors.forename: Altaf A
authors.initials: AA
authors.lastname: Lal
authors.forename: Lihua
authors.initials: L
authors.lastname: Xiao
mesh_terms: D000199:Actins / Q000737:chemistry / Q000235:genetics*; D000818:Animals; D001483:Base Sequence; D003458:Cryptosporidium / Q000737:chemistry / Q000235:genetics*; D016054:DNA, Protozoan / Q000737:chemistry / Q000235:genetics; D019143:Evolution, Molecular; D006801:Humans; D008969:Molecular Sequence Data; D009865:Oocytes / Q000737:chemistry; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D012689:Sequence Homology, Nucleic Acid
chemical_list: D000199:Actins; D016054:DNA, Protozoan