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

Autor:	Zwonitzer KD; Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712., Tressel LG; Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712., Wu Z; Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China., Kan S; Shenzhen Branch, Guangdong Laboratory of Lingnan Modern Agriculture, Key Laboratory of Synthetic Biology, Laboratory of the Ministry of Agriculture and Rural Affairs, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen 518000, China.; Marine College, Shandong University, Weihai 264209, China., Broz AK; Department of Biology, Colorado State University, Fort Collins, CO 80523., Mower JP; Department of Agronomy and Horticulture, University of Nebraska-Lincoln, Lincoln, NE 68588., Ruhlman TA; Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712., Jansen RK; Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712., Sloan DB; Department of Biology, Colorado State University, Fort Collins, CO 80523., Havird JC; Department of Integrative Biology, The University of Texas at Austin, Austin, TX 78712.
Jazyk:	angličtina
Zdroj:	Proceedings of the National Academy of Sciences of the United States of America [Proc Natl Acad Sci U S A] 2024 Mar 05; Vol. 121 (10), pp. e2317240121. Date of Electronic Publication: 2024 Mar 01.
DOI:	10.1073/pnas.2317240121
Abstrakt:	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. Competing Interests: Competing interests statement:The authors declare no competing interest.
Databáze:	MEDLINE
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