Introduction

The mitochondrial genomes of seed plants are unusually large and vary in size by at least an order of magnitude. Much of this variation occurs within a single family, the Cucurbitaceae, whose genomes range from an estimated 390 to 2,900 kb in size. We sequenced the mitochondrial genomes of Citrullus lanatus (watermelon: 379,236 nt) and Cucurbita pepo (zucchini: 982,833 nt)--the two smallest characterized cucurbit mitochondrial genomes--and determined their RNA editing content. The relatively compact Citrullus mitochondrial genome actually contains more and longer genes and introns, longer segmental duplications, and more discernibly nuclear-derived DNA. The large size of the Cucurbita mitochondrial genome reflects the accumulation of unprecedented amounts of both chloroplast sequences (>113 kb) and short repeated sequences (>370 kb). A low mutation rate has been hypothesized to underlie increases in both genome size and RNA editing frequency in plant mitochondria. However, despite its much larger genome, Cucurbita has a significantly higher synonymous substitution rate (and presumably mutation rate) than Citrullus but comparable levels of RNA editing. The evolution of mutation rate, genome size, and RNA editing are apparently decoupled in Cucurbitaceae, reflecting either simple stochastic variation or governance by different factors.

Publications

  1. Insights into the evolution of mitochondrial genome size from complete sequences of Citrullus lanatus and Cucurbita pepo (Cucurbitaceae).
    Cite this
    Alverson AJ, Wei X, Rice DW, Stern DB, Barry K, Palmer JD, 2010-06-01 - Molecular biology and evolution

Credits

  1. Andrew J Alverson
    Developer

    Department of Biology, Indiana University

  2. XiaoXin Wei
    Developer

  3. Danny W Rice
    Developer

  4. David B Stern
    Developer

  5. Kerrie Barry
    Developer

  6. Jeffrey D Palmer
    Investigator

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Summary
AccessionBT001972
Tool TypeApplication
Category
PlatformsLinux/Unix
TechnologiesPerl
User InterfaceTerminal Command Line
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Submitted ByJeffrey D Palmer