Behera N, Nanjundiah V
Developmental Biology and Genetics Laboratory, Indian Institute of Science, Bangalore, India.
J Theor Biol. 1996 Jan 21;178(2):135-44. doi: 10.1006/jtbi.1996.0012.
By "phenotypic plasticity" we refer to the capacity of a genotype to exhibit different phenotypes, whether in the same or in different environments. We have previously demonstrated that phenotypic plasticity can improve the degree of adaptation achieved via natural selection (Behera & Nanjundiah, 1995). That result was obtained from a genetic algorithm model of haploid genotypes (idealized as one-dimensional strings of genes) evolving in a fixed environment. Here, the dynamics of evolution is examined under conditions of a cyclically varying environment. We find that the rate of evolution, as well as the extent of adaptation (as measured by mean population fitness) is lowered because of environmental cycling. The decrease in adaptation caused by a varying environment can, however, be partly or wholly compensated by an increase in the degree of plasticity that a genotype is capable of. Also, the reduction of population fitness caused by a variable environment can be partially offset by decreasing the total number of genetic loci. We conjecture that an increase in genome size may have been among the factors responsible for the evolution of phenotypic plasticity.
我们所说的“表型可塑性”是指基因型在相同或不同环境中表现出不同表型的能力。我们之前已经证明，表型可塑性可以提高通过自然选择实现的适应程度（贝赫拉和南君迪亚，1995年）。该结果是通过在固定环境中进化的单倍体基因型（理想化地表示为一维基因串）的遗传算法模型获得的。在这里，我们研究了在环境周期性变化的条件下的进化动态。我们发现，由于环境循环，进化速率以及适应程度（以平均种群适合度衡量）都会降低。然而，由变化的环境导致的适应度下降可以部分或全部通过基因型能够表现出的可塑性程度的增加来补偿。此外，可变环境导致的种群适合度降低可以通过减少基因座总数来部分抵消。我们推测基因组大小的增加可能是导致表型可塑性进化的因素之一。
