Oliver Matthew J, Petrov Dmitri, Ackerly David, Falkowski Paul, Schofield Oscar M
Institute of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey 08901, USA.
Genome Res. 2007 May;17(5):594-601. doi: 10.1101/gr.6096207. Epub 2007 Apr 9.
Eukaryotic genome size varies over five orders of magnitude; however, the distribution is strongly skewed toward small values. Genome size is highly correlated to a number of phenotypic traits, suggesting that the relative lack of large genomes in eukaryotes is due to selective removal. Using phylogenetic contrasts, we show that the rate of genome size evolution is proportional to genome size, with the fastest rates occurring in the largest genomes. This trend is evident across the 20 major eukaryotic clades analyzed, indicating that over long time scales, proportional change is the dominant and universal mode of genome-size evolution in eukaryotes. Our results reveal that the evolution of eukaryotic genome size can be described by a simple proportional model of evolution. This model explains the skewed distribution of eukaryotic genome sizes without invoking strong selection against large genomes.
真核生物的基因组大小在五个数量级上有所不同；然而，其分布强烈偏向于较小的值。基因组大小与许多表型特征高度相关，这表明真核生物中相对缺乏大基因组是由于选择性去除。通过系统发育对比，我们表明基因组大小的进化速率与基因组大小成正比，最大的基因组进化速率最快。这种趋势在分析的20个主要真核生物分支中都很明显，表明在长时间尺度上，比例变化是真核生物基因组大小进化的主要和普遍模式。我们的结果表明，真核生物基因组大小的进化可以用一个简单的比例进化模型来描述。该模型解释了真核生物基因组大小的偏态分布，而无需对大基因组进行强烈选择。
