植物种群分子进化中对生境的适应——对荒漠植物遗传多样性研究结果的初步分析

Environmental adaptation in plant population in the process of molecular evolution ——Primary analysis of the result from the study on the genetic diversity of the desert plants

长期以来 ,自然选择理论与中性理论对生物分子进化中的环境适应机理存在着激烈争论 .目前 ,在植物种群分子进化中对生境适应的研究中正面临着一些难题 :中性突变是分子水平进化的唯一原因 ,自然选择发挥主要作用的适应性进化是否存在于分子水平 ,选择与中性两种学说两种机制完全不同 ,如何才能将两者联系和统一起来 ,部分学者利用建立各种模型来描述自然选择对分子标记位点以及连锁序列的直接作用 ,如生态位宽度变异假设等 .本研究小组以新疆阜康荒漠植物为研究对象 ,通过对两种重要荒漠植物遗传多样性的研究 ,分析两种植物各亚种群不同生境的生态因子与其遗传变异的关系 ,讨论生态位宽度变异假设 ,揭示遗传变异的产生与维持 .中性论者与选择论者都试图解释生物环境适应与分子变异之间的关系 .中性论和选择论是反映进化的两个侧面 ,它们不是绝对的 。

There has been the deep discussion between the natural selection theory and the neutral theory for the long time. Presently, the difficult problems exist in the study on the environmental adaptation in the process of molecular evolution in plant population: Is the neutral mutation the only reason for the molecular evolution? Does the adaptative evolution driven greatly by the natural selection exist at the molecular level? How can the two different theories and mechanisms be connected and unified? The scholars established the models to describe the direct effect of the natural selection on the molecular markers and the linkage sequences, such as the hypothesis of the variation of the width of niche. The result of our study on the relationship between the genetic variation and the ecological factors in the respective microenvironment of the desert plants in Fukang, Xinjiang, confirmed the hypothesis of the variation of the width of niche and discussed the form and maintenance of the genetic variation. The scientists both from the neutral theory and the selection theory are devoted to explaining the relationship between the molecular variation and the environmental adaptation. The neutral theory and the selection theory are the two sides of the evolution. In fact, they do not contradict to each other, and eventually, they can convert to each other.