Long-read assembly and comparative evidence-based reanalysis of Cryptosporidium genome sequences reveals expanded transporter repertoire and duplication of entire chromosome ends including subtelomeric regions
Details
Publication Year 2022-01-01,Volume 32,Issue #1,Page 203-213
Journal Title
Genome Research
Abstract
Cryptosporidiosis is a leading cause of waterborne diarrheal disease globally and an important contributor to mortality in infants and the immunosuppressed. Despite its importance, the Cryptosporidium community has only had access to a good, but incomplete, Cryptosporidium parvum IOWA reference genome sequence. Incomplete reference sequences hamper annotation, experimental design and interpretation. We have generated a new C. parvum IOWA genome assembly supported by PacBio and Oxford Nanopore long-read technologies and a new comparative and consistent genome annotation for three closely related species C. parvum, Cryptosporidium hominis and Cryptosporidium tyzzeri We made 1,926 C. parvum annotation updates based on experimental evidence. They include new transporters, ncRNAs, introns and altered gene structures. The new assembly and annotation revealed a complete Dnmt2 methylase ortholog. Comparative annotation between C. parvum, C. hominis and C. tyzzeri revealed that most "missing" orthologs are found suggesting that the biological differences between the species must result from gene copy number variation, differences in gene regulation and single nucleotide variants (SNVs). Using the new assembly and annotation as reference, 190 genes are identified as evolving under positive selection, including many not detected previously. The new C. parvum IOWA reference genome assembly is larger, gap free and lacks ambiguous bases. This chromosomal assembly recovers all 16 chromosome ends, 13 of which are contiguously assembled. The three remaining chromosome ends are provisionally placed. These ends represent duplication of entire chromosome ends including subtelomeric regions revealing a new level of genome plasticity that will both inform and impact future research.
Publisher
CSHLP
Research Division(s)
Population Health And Immunity
PubMed ID
34764149
Open Access at Publisher's Site
https://doi.org/10.1101/gr.275325.121
Terms of Use/Rights Notice
Refer to copyright notice on published article.


Creation Date: 2021-12-07 12:03:54
Last Modified: 2022-02-18 04:06:44
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