title: The genome of Cryptosporidium hominis.
abstract: Cryptosporidium species cause acute gastroenteritis and diarrhoea worldwide. They are members of the Apicomplexa--protozoan pathogens that invade host cells by using a specialized apical complex and are usually transmitted by an invertebrate vector or intermediate host. In contrast to other Apicomplexans, Cryptosporidium is transmitted by ingestion of oocysts and completes its life cycle in a single host. No therapy is available, and control focuses on eliminating oocysts in water supplies. Two species, C. hominis and C. parvum, which differ in host range, genotype and pathogenicity, are most relevant to humans. C. hominis is restricted to humans, whereas C. parvum also infects other mammals. Here we describe the eight-chromosome approximately 9.2-million-base genome of C. hominis. The complement of C. hominis protein-coding genes shows a striking concordance with the requirements imposed by the environmental niches the parasite inhabits. Energy metabolism is largely from glycolysis. Both aerobic and anaerobic metabolisms are available, the former requiring an alternative electron transport system in a simplified mitochondrion. Biosynthesis capabilities are limited, explaining an extensive array of transporters. Evidence of an apicoplast is absent, but genes associated with apical complex organelles are present. C. hominis and C. parvum exhibit very similar gene complements, and phenotypic differences between these parasites must be due to subtle sequence divergence.
authors.affiliation: Center for the Study of Biological Complexity, Virginia Commonwealth University, Richmond, Virginia 23284-2030, USA.
authors.forename: Ping
authors.initials: P
authors.lastname: Xu
authors.forename: Giovanni
authors.initials: G
authors.lastname: Widmer
authors.forename: Yingping
authors.initials: Y
authors.lastname: Wang
authors.forename: Luiz S
authors.initials: LS
authors.lastname: Ozaki
authors.forename: Joao M
authors.initials: JM
authors.lastname: Alves
authors.forename: Myrna G
authors.initials: MG
authors.lastname: Serrano
authors.forename: Daniela
authors.initials: D
authors.lastname: Puiu
authors.forename: Patricio
authors.initials: P
authors.lastname: Manque
authors.forename: Donna
authors.initials: D
authors.lastname: Akiyoshi
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Mackey
authors.forename: William R
authors.initials: WR
authors.lastname: Pearson
authors.forename: Paul H
authors.initials: PH
authors.lastname: Dear
authors.forename: Alan T
authors.initials: AT
authors.lastname: Bankier
authors.forename: Darrell L
authors.initials: DL
authors.lastname: Peterson
authors.forename: Mitchell S
authors.initials: MS
authors.lastname: Abrahamsen
authors.forename: Vivek
authors.initials: V
authors.lastname: Kapur
authors.forename: Saul
authors.initials: S
authors.lastname: Tzipori
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Buck
mesh_terms: D000818:Animals; D002875:Chromosomes / Q000235:genetics; D003458:Cryptosporidium / Q000145:classification / Q000201:enzymology / Q000235:genetics* / Q000378:metabolism; D016785:Cryptosporidium parvum / Q000235:genetics; D004798:Enzymes / Q000235:genetics; D019143:Evolution, Molecular; D017125:Genes, Protozoan / Q000235:genetics; D018503:Genome, Protozoan; D023281:Genomics; D006801:Humans; D010641:Phenotype; D015800:Protozoan Proteins / Q000235:genetics
chemical_list: D004798:Enzymes; D015800:Protozoan Proteins