Shapiro J A
Department of Biochemistry and Molecular Biology, University of Chicago, Illinois 60637, USA.
Ann N Y Acad Sci. 1999 May 18;870:23-35. doi: 10.1111/j.1749-6632.1999.tb08862.x.
Molecular genetics teaches three lessons relevant to the nature of genetic change during evolution: (1) Genomes are organized as hierarchies of composite systems (multidomain protein-coding sequences; functional loci made up of regulatory, coding, processing, and intervening sequences; and multilocus regulons and replicons) interconnected and organized into specific "system architectures" by repetitive DNA elements. (2) Genetic change often occurs via natural genetic engineering systems (cellular biochemical functions, such as recombination complexes, topoisomerases, and mobile elements, capable of altering DNA sequence information and joining together different genomic components). (3) The activity of natural genetic systems is regulated by cellular control circuits with respect to the timing, activity levels, and specificities of DNA rearrangements (e.g., adaptive mutation, Ty element mobility, and P factor insertions). These three lessons provide plausible molecular explanations for the episodic, multiple, nonrandom DNA rearrangements needed to account for the evolution of novel genomic system architectures and complex multilocus adaptations. This molecular genetic perspective places evolutionary change in the biologically responsive context of cellular biochemistry.
（1）基因组以复合系统层次结构的形式组织起来（多结构域蛋白质编码序列；由调控、编码、加工和间隔序列组成的功能基因座；以及多位点调控子和复制子），通过重复DNA元件相互连接并组织成特定的“系统架构”。（2）基因变化通常通过自然基因工程系统发生（细胞生化功能，如重组复合体、拓扑异构酶和移动元件，能够改变DNA序列信息并将不同的基因组组分连接在一起）。（3）自然遗传系统的活性在DNA重排的时间、活性水平和特异性方面受到细胞控制回路的调节（例如适应性突变、Ty元件移动性和P因子插入）。这三条经验为解释新型基因组系统架构和复杂多位点适应性进化所需的偶发性、多重、非随机DNA重排提供了合理的分子解释。这种分子遗传学观点将进化变化置于细胞生物化学的生物响应背景之中。
