Extraordinary genome stability in the ciliate Paramecium tetraurelia.
نویسندگان
چکیده
Mutation plays a central role in all evolutionary processes and is also the basis of genetic disorders. Established base-substitution mutation rates in eukaryotes range between ∼5 × 10(-10) and 5 × 10(-8) per site per generation, but here we report a genome-wide estimate for Paramecium tetraurelia that is more than an order of magnitude lower than any previous eukaryotic estimate. Nevertheless, when the mutation rate per cell division is extrapolated to the length of the sexual cycle for this protist, the measure obtained is comparable to that for multicellular species with similar genome sizes. Because Paramecium has a transcriptionally silent germ-line nucleus, these results are consistent with the hypothesis that natural selection operates on the cumulative germ-line replication fidelity per episode of somatic gene expression, with the germ-line mutation rate per cell division evolving downward to the lower barrier imposed by random genetic drift. We observe ciliate-specific modifications of widely conserved amino acid sites in DNA polymerases as one potential explanation for unusually high levels of replication fidelity.
منابع مشابه
ParameciumDB in 2011: new tools and new data for functional and comparative genomics of the model ciliate Paramecium tetraurelia
ParameciumDB is a community model organism database built with the GMOD toolkit to integrate the genome and biology of the ciliate Paramecium tetraurelia. Over the last four years, post-genomic data from proteome and transcriptome studies has been incorporated along with predicted orthologs in 33 species, annotations from the community and publications from the scientific literature. Available ...
متن کاملDraft Genome Sequence of Holospora undulata Strain HU1, a Micronucleus-Specific Symbiont of the Ciliate Paramecium caudatum
Holospora undulata is a micronucleus-specific symbiont of the ciliate Paramecium caudatum. We report here the draft genome sequence of H. undulata strain HU1. This genome information will contribute to the study of symbiosis between H. undulata and the host P. caudatum.
متن کاملLow base-substitution mutation rate in the ciliate Tetrahymena thermophila
Mutation is the ultimate source of all genetic variation and is, therefore, central to evolutionary change. Previous work on the ciliate Paramecium tetraurelia concluded that the presence of a transcriptionally silent germline genome has caused the evolution of a low base-substitution mutation rate in the germline genome of that ciliate. Here, we use mutation accumulation (MA) lines of the cili...
متن کاملLarge-scale genome remodelling by the developmentally programmed elimination of germ line sequences in the ciliate Paramecium.
In Paramecium, during the development of the somatic macronucleus, precise excision of thousands of single-copy non-coding sequences is initiated by specific DNA double-strand breaks, while imprecise elimination of germ-line-limited repeated sequences leads to internal deletions or chromosome fragmentation. Recent data point to a role of non-coding RNAs in the epigenetic programming of these re...
متن کاملGenome-Wide Analysis of the Phosphoinositide Kinome from Two Ciliates Reveals Novel Evolutionary Links for Phosphoinositide Kinases in Eukaryotic Cells
BACKGROUND The complexity of phosphoinositide signaling in higher eukaryotes is partly due to expansion of specific families and types of phosphoinositide kinases (PIKs) that can generate all phosphoinositides via multiple routes. This is particularly evident in the PI3Ks and PIPKs, and it is considered an evolutionary trait associated with metazoan diversification. Yet, there are limited compr...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Proceedings of the National Academy of Sciences of the United States of America
دوره 109 47 شماره
صفحات -
تاریخ انتشار 2012