Differential evolution of repetitive sequences in Cryptosporidium parvum and Cryptosporidium hominis

作者：Tanriverdi S; Widmer G^*

来源：Infection, Genetics and Evolution, 2006, 6(2): 113-122.

DOI：10.1016/j.meegid.2005.02.002

• Cryptosporidium parvum
• Cryptosporidium hominis
• minisatellite
• microsatellite
• genetic polymorphism
• length polymorphism

Cryptosporidium parvum and Cryptosporidium hominis are two morphologically identical species of Apicomplexan protozoa infecting humans. Although the genomes of these species are 97% identical, their host range is strikingly different. C. parvum infects humans and animals and is primarily a zoonotic infection, whereas C hominis is typically not detected in animals. The extent of genetic polymorphism in both species has been surveyed locally, but not on a larger geographical scale. Herein, a collection of unrelated C parvum and C. hominis isolates was genotyped using multiple, randomly distributed micro- and minisatellites. In average, minisatellites, consisting of tandemly repeated sequence motifs of 6-24 basepair, were more polymorphic than microsatellites. When the average number of micro- and minisatellite alleles per locus was used as a measure of heterogeneity, no difference between C. parvum and C hominis was found. However, the frequency distribution of alleles in both species was significantly different and in 6 of the 14 loci the size of the C. parvum and C. hominis repeats did not overlap. Assuming that C. parvum and C. hominis evolved from a common ancestor, these observations suggest a differential evolution of repeat length at these loci.

• 出版日期2006-3