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Genomic analysis finds no evidence of canonical eukaryotic DNA processing complexes in a free-living protist.

Published version
Peer-reviewed

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Abstract

Cells replicate and segregate their DNA with precision. Previous studies showed that these regulated cell-cycle processes were present in the last eukaryotic common ancestor and that their core molecular parts are conserved across eukaryotes. However, some metamonad parasites have secondarily lost components of the DNA processing and segregation apparatuses. To clarify the evolutionary history of these systems in these unusual eukaryotes, we generated a genome assembly for the free-living metamonad Carpediemonas membranifera and carried out a comparative genomics analysis. Here, we show that parasitic and free-living metamonads harbor an incomplete set of proteins for processing and segregating DNA. Unexpectedly, Carpediemonas species are further streamlined, lacking the origin recognition complex, Cdc6 and most structural kinetochore subunits. Carpediemonas species are thus the first known eukaryotes that appear to lack this suite of conserved complexes, suggesting that they likely rely on yet-to-be-discovered or alternative mechanisms to carry out these fundamental processes.

Description

Funder: Canadian Institutes of Health Research (Grant: FRN-142349) Natural Sciences and Engineering Research Council of Canada (Grant: RGPIN 05871-2014)

Keywords

Animals, Biological Evolution, DNA, Eukaryota, Eukaryotic Cells, Genome, Genomics, Microbiology, Parasites, Proteins

Journal Title

Nat Commun

Conference Name

Journal ISSN

2041-1723
2041-1723

Volume Title

12

Publisher

Springer Science and Business Media LLC