文献类型：期刊文献

英文题名：Comparative genomic analysis reveals occurrence of genetic recombination in virulent Cryptosporidium hominis subtypes and telomeric gene duplications in Cryptosporidium parvum

作者：Guo, Yaqiong[1,2];Tang, Kevin[3];Rowe, Lori A.[3];Li, Na[1];Roellig, Dawn M.[2];Knipe, Kristine[3];Frace, Michael[3];Yang, Chunfu[4];Feng, Yaoyu[1];Xiao, Lihua[2]

机构：[1]E China Univ Sci & Technol, Sch Resources & Environm Engn, State Key Lab Bioreactor Engn, Shanghai 200237, Peoples R China;[2]Ctr Dis Control & Prevent, Divis Foodborne Waterborne & Environm Dis, Atlanta, GA 30333 USA;[3]Ctr Dis Control & Prevent, Div Sci Resources, Atlanta, GA 30333 USA;[4]Ctr Dis Control & Prevent, Div Global HIV AIDS, Atlanta, GA 30333 USA

年份：2015

卷号：16

外文期刊名：BMC GENOMICS

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000353390700001)】；

基金：We thank Scott Sammons of the Centers for Disease Control and Prevention for technical assistance. This work was supported by the National Natural Science Foundation of China (31229005, 31425025 and 31110103901), National Special Fund for State Key Laboratory of Bioreactor Engineering, China (No. 2060204), and Centers for Disease Control and Prevention, USA. The findings and conclusions in this report are those of the authors and do not necessarily represent the views of the Centers for Disease Control and Prevention.

语种：英文

外文关键词：Cryptosporidium; Genomics; Whole genome sequencing; Genetic recombination; Virulence

摘要：Background: Cryptosporidium hominis is a dominant species for human cryptosporidiosis. Within the species, IbA10G2 is the most virulent subtype responsible for all C. hominis-associated outbreaks in Europe and Australia, and is a dominant outbreak subtype in the United States. In recent yearsIaA28R4 is becoming a major new subtype in the United States. In this study, we sequenced the genomes of two field specimens from each of the two subtypes and conducted a comparative genomic analysis of the obtained sequences with those from the only fully sequenced Cryptosporidium parvum genome. Results: Altogether, 8.59-9.05 Mb of Cryptosporidium sequences in 45-767 assembled contigs were obtained from the four specimens, representing 94.36-99.47% coverage of the expected genome. These genomes had complete synteny in gene organization and 96.86-97.0% and 99.72-99.83% nucleotide sequence similarities to the published genomes of C. parvum and C. hominis, respectively. Several major insertions and deletions were seen between C. hominis and C. parvum genomes, involving mostly members of multicopy gene families near telomeres. The four C. hominis genomes were highly similar to each other and divergent from the reference IaA25R3 genome in some highly polymorphic regions. Major sequence differences among the four specimens sequenced in this study were in the 5' and 3' ends of chromosome 6 and the gp60 region, largely the result of genetic recombination. Conclusions: The sequence similarity among specimens of the two dominant outbreak subtypes and genetic recombination in chromosome 6, especially around the putative virulence determinant gp60 region, suggest that genetic recombination plays a potential role in the emergence of hyper-transmissible C. hominis subtypes. The high sequence conservation between C. parvum and C. hominis genomes and significant differences in copy numbers of MEDLE family secreted proteins and insulinase-like proteases indicate that telomeric gene duplications could potentially contribute to host expansion in C. parvum.