Molecular Ecology and Evolution
Guisinger-Bellian, Mary M. , Boore, Jeffrey , Kuehl, Jennifer V. , Jansen, Robert K. .
Genome-wide analyses reveal patterns of increased nonsynonymous substitutions in plastids of the flowering plant family Geraniaceae.
Land plant plastid genomes are generally highly conserved in terms of gene content and order, and the rate of sequence evolution for protein-coding genes is lower than for nuclear genes. Yet, a few groups have experienced genomic change, including the flowering plant family Geraniaceae. The Geraniaceae plastid genome of Pelargonium x hortorum has been completely sequenced, and it was found to be the largest (217,942 bp) and most rearranged land plant plastid genome yet sequenced. Nearly complete draft sequences are available for eight additional taxa of Geraniaceae, Erodium texanum, E. chrysanthum, Pelargonium cotyledonis, Geranium palmatum, G. macrorrhizum, G. carolinianum, Monsonia speciosa, and M. vanderietieae, including at least one sequence for every genus within the family. Finishing of these genomes is in progress. The nearly complete Geraniaceae plastid genomes exhibit a number of remarkable features, including extensive genome rearrangement and numerous gene and intron losses throughout the family. Geraniaceae is also well known for highly elevated rates of sequence evolution in the mitochondrial genome of certain lineages of Pelargonium. Although rates of sequence evolution are correlated to rates of genomic rearrangement in arthropod mitochondrial genomes, such correlations have not been thoroughly tested in plastid genomes. Extensive statistical comparisons of rates of nucleotide substitutions in 72 plastid genes for 47 angiosperm taxa, including nine Geraniaceae, show that rates of nonsynonymous substitutions are accelerated in ribosomal protein genes and RNA polymerase genes throughout the family relative to other angiosperms. Moreover, the ratio of nonsynonymous substitutions to synonymous substitutions is significantly higher is ribosomal protein genes, ATPase genes, and RNA polymerase genes in Geraniaceae relative to other angiosperms.
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1 - University of Texas Austin, Section of Integrative Biology, 1 University Station, A6700, Austin, Texas, 78712-7640, USA
2 - Genome Project Solutions, 1024 Promenade Street, Hercules, CA, 94702, USA
3 - DOE Joint Genome Institute and Lawrence Berkeley National Lab, Evolutionary Genomics Program, 2800 Mitchell Drive, Walnut Creek, California, 94598, USA
Presentation Type: Poster:Posters for Topics
Location: Ball Room & Party Room/SUB
Date: Monday, July 28th, 2008
Time: 12:30 PM