Phylogenetic relationships of Cryptosporidium parasites based on the 70-kilodalton heat shock protein (HSP70) gene

We have characterized the nucleotide sequences of the 70-kDa heat shock pro tein (HSP70) genes of Cryptosporidium baileyi, C. felis, C. meleagridis, C. muris, C. serpentis, C. wrairi, and C. parvum from various animals. Result s of the phylogenetic analysis revealed the presence of several genetically distinct species in the genus Cryptosporidium and eight distinct genotypes within the species C. parvum. Some of the latter may represent cryptic spe cies. The phylogenetic tree constructed from these sequences is in agreemen t with our previous results based on the small-subunit rRNA genes of Crypto sporidium parasites. The Cryptosporidium species formed two major clades: i solates of C. muris and C. serpentis formed the first major group, while is olates of C. felis, C. meleagridis, C. wrairi, and eight genotypes of C. pa rvum formed the second major group. Sequence variations were also observed between C. muris isolates from ruminants and rodents. The HSP70 gene provid es another useful locus for phylogenetic analysis of the genus Cryptosporid ium.