Genome copy number predicts extreme evolutionary rate variation in plant mitochondrial DNA

文献类型： 外文期刊

第一作者： Zwonitzer, Kendra D.

作者： Zwonitzer, Kendra D.;Tressel, Lydia G.;Ruhlman, Tracey A.;Jansen, Robert K.;Havird, Justin C.;Wu, Zhiqiang;Kan, Shenglong;Kan, Shenglong;Broz, Amanda K.;Sloan, Daniel B.;Mower, Jeffrey P.

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关键词： plant mitogenome; mtDNA; substitution rate; copy number; plastome

期刊名称：PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA （ 影响因子：11.1； 五年影响因子：12.0 ）

ISSN： 0027-8424

年卷期： 2024 年 121 卷 10 期

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收录情况： SCI

摘要： Nuclear and organellar genomes can evolve at vastly different rates despite occupying the same cell. In most bilaterian animals, mitochondrial DNA (mtDNA) evolves faster than nuclear DNA, whereas this trend is generally reversed in plants. However, in some exceptional angiosperm clades, mtDNA substitution rates have increased up to 5,000 - fold compared with closely related lineages. The mechanisms responsible for this acceleration are generally unknown. Because plants rely on homologous recombination to repair mtDNA damage, we hypothesized that mtDNA copy numbers may predict evolutionary rates, as lower copy numbers may provide fewer templates for such repair mechanisms. In support of this hypothesis, we found that copy number explains 47% of the variation in synonymous substitution rates of mtDNA across 60 diverse seed plant species representing -300 million years of evolution. Copy number was also negatively correlated with mitogenome size, which may be a cause or consequence of mutation rate variation. Both relationships were unique to mtDNA and not observed in plastid DNA. These results suggest that homologous recombinational repair plays a role in driving mtDNA substitution rates in plants and may explain variation in mtDNA evolution more broadly across eukaryotes. Our findings also contribute to broader questions about the relationships between mutation rates, genome size, selection efficiency, and the drift- barrier hypothesis.

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