The mode and tempo of genome size evolution in the subgenus Sophophora.

Genome size varies widely across organisms, with no apparent tie to organismal complexity. While genome size is inherited, there is no established evolutionary model for this trait. Hypotheses have been postulated for the observed variation in genome sizes across species, most notably the effective...

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Main Authors: Carl E Hjelmen, J Spencer Johnston
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2017-01-01
Series:PLoS ONE
Online Access:http://europepmc.org/articles/PMC5340367?pdf=render
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author Carl E Hjelmen
J Spencer Johnston
author_facet Carl E Hjelmen
J Spencer Johnston
author_sort Carl E Hjelmen
collection DOAJ
description Genome size varies widely across organisms, with no apparent tie to organismal complexity. While genome size is inherited, there is no established evolutionary model for this trait. Hypotheses have been postulated for the observed variation in genome sizes across species, most notably the effective population size hypothesis, the mutational equilibrium hypothesis, and the adaptive hypothesis. While much data has been collected on genome size, the above hypotheses have largely ignored impacts from phylogenetic relationships. In order to test these competing hypotheses, genome sizes of 87 Sophophora species were analyzed in a comparative phylogenetic approach using Pagel's parameters of evolution, Blomberg's K, Abouheif's Cmean and Moran's I. In addition to testing the mode and rate of genome size evolution in Sophophora species, the effect of number of taxa on detection of phylogenetic signal was analyzed for each of these comparative phylogenetic methods. Sophophora genome size was found to be dependent on the phylogeny, indicating that evolutionary time was important for predicting the variation among species. Genome size was found to evolve gradually on branches of the tree, with a rapid burst of change early in the phylogeny. These results suggest that Sophophora genome size has experienced gradual changes, which support the largely theoretical mutational equilibrium hypothesis. While some methods (Abouheif's Cmean and Moran's I) were found to be affected by increasing taxa numbers, more commonly used methods (λ and Blomberg's K) were found to have increasing reliability with increasing taxa number, with significantly more support with fifteen or more taxa. Our results suggest that these comparative phylogenetic methods, with adequate taxon sampling, can be a powerful way to uncover the enigma that is genome size variation through incorporation of phylogenetic relationships.
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spelling doaj.art-ff2e005376ec4ea8b81b7976e354d7a72022-12-21T18:44:09ZengPublic Library of Science (PLoS)PLoS ONE1932-62032017-01-01123e017350510.1371/journal.pone.0173505The mode and tempo of genome size evolution in the subgenus Sophophora.Carl E HjelmenJ Spencer JohnstonGenome size varies widely across organisms, with no apparent tie to organismal complexity. While genome size is inherited, there is no established evolutionary model for this trait. Hypotheses have been postulated for the observed variation in genome sizes across species, most notably the effective population size hypothesis, the mutational equilibrium hypothesis, and the adaptive hypothesis. While much data has been collected on genome size, the above hypotheses have largely ignored impacts from phylogenetic relationships. In order to test these competing hypotheses, genome sizes of 87 Sophophora species were analyzed in a comparative phylogenetic approach using Pagel's parameters of evolution, Blomberg's K, Abouheif's Cmean and Moran's I. In addition to testing the mode and rate of genome size evolution in Sophophora species, the effect of number of taxa on detection of phylogenetic signal was analyzed for each of these comparative phylogenetic methods. Sophophora genome size was found to be dependent on the phylogeny, indicating that evolutionary time was important for predicting the variation among species. Genome size was found to evolve gradually on branches of the tree, with a rapid burst of change early in the phylogeny. These results suggest that Sophophora genome size has experienced gradual changes, which support the largely theoretical mutational equilibrium hypothesis. While some methods (Abouheif's Cmean and Moran's I) were found to be affected by increasing taxa numbers, more commonly used methods (λ and Blomberg's K) were found to have increasing reliability with increasing taxa number, with significantly more support with fifteen or more taxa. Our results suggest that these comparative phylogenetic methods, with adequate taxon sampling, can be a powerful way to uncover the enigma that is genome size variation through incorporation of phylogenetic relationships.http://europepmc.org/articles/PMC5340367?pdf=render
spellingShingle Carl E Hjelmen
J Spencer Johnston
The mode and tempo of genome size evolution in the subgenus Sophophora.
PLoS ONE
title The mode and tempo of genome size evolution in the subgenus Sophophora.
title_full The mode and tempo of genome size evolution in the subgenus Sophophora.
title_fullStr The mode and tempo of genome size evolution in the subgenus Sophophora.
title_full_unstemmed The mode and tempo of genome size evolution in the subgenus Sophophora.
title_short The mode and tempo of genome size evolution in the subgenus Sophophora.
title_sort mode and tempo of genome size evolution in the subgenus sophophora
url http://europepmc.org/articles/PMC5340367?pdf=render
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