Astonishing 35S rDNA diversity in the gymnosperm species Cycas revoluta Thunb

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F68081707%3A_____%2F16%3A00470767" target="_blank" >RIV/68081707:_____/16:00470767 - isvavai.cz</a>

Result on the web

<a href="http://dx.doi.org/10.1007/s00412-015-0556-3" target="_blank" >http://dx.doi.org/10.1007/s00412-015-0556-3</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1007/s00412-015-0556-3" target="_blank" >10.1007/s00412-015-0556-3</a>

Result language

angličtina

Original language name

Astonishing 35S rDNA diversity in the gymnosperm species Cycas revoluta Thunb

Original language description

In all eukaryotes, the highly repeated 35S ribosomal DNA (rDNA) sequences encoding 18S-5.8S-26S ribosomal RNA (rRNA) typically show high levels of intragenomic uniformity due to homogenisation processes, leading to concerted evolution of 35S rDNA repeats. Here, we compared 35S rDNA divergence in several seed plants using next generation sequencing and a range of molecular and cytogenetic approaches. Most species showed similar 35S rDNA homogeneity indicating concerted evolution. However, Cycas revoluta exhibits an extraordinary diversity of rDNA repeats (nucleotide sequence divergence of different copies averaging 12 %), influencing both the coding and non-coding rDNA regions nearly equally. In contrast, its rRNA transcriptome was highly homogeneous suggesting that only a minority of genes (< 20 %) encode functional rRNA. The most common SNPs were C > T substitutions located in symmetrical CG and CHG contexts which were also highly methylated. Both functional genes and pseudogenes appear to cluster on chromosomes. The extraordinary high levels of 35S rDNA diversity in C. revoluta, and probably other species of cycads, indicate that the frequency of repeat homogenisation has been much lower in this lineage, compared with all other land plant lineages studied. This has led to the accumulation of methylation-driven mutations and pseudogenisation. Potentially, the reduced homology between paralogs prevented their elimination by homologous recombination, resulting in long-term retention of rDNA pseudogenes in the genome.

Czech name

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Czech description

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Type

J_x - Unclassified - Peer-reviewed scientific article (Jimp, Jsc and Jost)

CEP classification

BO - Biophysics

OECD FORD branch

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Project

Result was created during the realization of more than one project. More information in the Projects tab.

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Publication year

2016

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Chromosoma

ISSN

0009-5915

e-ISSN

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Volume of the periodical

125

Issue of the periodical within the volume

4

Country of publishing house

DE - GERMANY

Number of pages

17

Pages from-to

683-699

UT code for WoS article

000383464800009

EID of the result in the Scopus database

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