Rando Oliver J, Verstrepen Kevin J
Department of Biochemistry and Molecular Pharmacology, University of Massachusetts Medical School, Worcester, MA 01605, USA.
Cell. 2007 Feb 23;128(4):655-68. doi: 10.1016/j.cell.2007.01.023.
According to classical evolutionary theory, phenotypic variation originates from random mutations that are independent of selective pressure. However, recent findings suggest that organisms have evolved mechanisms to influence the timing or genomic location of heritable variability. Hypervariable contingency loci and epigenetic switches increase the variability of specific phenotypes; error-prone DNA replicases produce bursts of variability in times of stress. Interestingly, these mechanisms seem to tune the variability of a given phenotype to match the variability of the acting selective pressure. Although these observations do not undermine Darwin's theory, they suggest that selection and variability are less independent than once thought.
根据经典进化理论，表型变异源于与选择压力无关的随机突变。然而，最近的研究结果表明，生物体已经进化出机制来影响可遗传变异的时间或基因组位置。高变偶然位点和表观遗传开关增加了特定表型的变异性；易出错的DNA复制酶在压力时期产生变异性爆发。有趣的是，这些机制似乎能调节给定表型的变异性，以匹配作用于其上的选择压力的变异性。尽管这些观察结果并未削弱达尔文的理论，但它们表明选择和变异性并不像人们曾经认为的那样相互独立。
