Purugganan M D, Suddith J I
Department of Genetics, North Carolina State University, Raleigh, North Carolina 27695, USA.
Genetics. 1999 Feb;151(2):839-48. doi: 10.1093/genetics/151.2.839.
Molecular variation in genes that regulate development provides insights into the evolutionary processes that shape the diversification of morphogenetic pathways. Intraspecific sequence variation at the APETALA3 and PISTILLATA floral homeotic genes of Arabidopsis thaliana was analyzed to infer the extent and nature of diversity at these regulatory loci. Comparison of AP3 and PI diversity with three previously studied genes revealed several features in the patterning of nucleotide polymorphisms common between Arabidopsis nuclear loci, including an excess of low-frequency nucleotide polymorphisms and significantly elevated levels of intraspecific replacement variation. This pattern suggests that A. thaliana has undergone recent, rapid population expansion and now exists in small, inbred subpopulations. The elevated intraspecific replacement levels may thus represent slightly deleterious polymorphisms that differentiate distinct ecotypes. The distribution of replacement and synonymous changes in AP3 and PI core and noncore functional domains also indicates differences in the patterns of molecular evolution between these interacting floral regulatory genes.
调控发育的基因中的分子变异为了解塑造形态发生途径多样化的进化过程提供了线索。分析了拟南芥花同源异型基因APETALA3和PISTILLATA的种内序列变异，以推断这些调控位点的多样性程度和性质。将AP3和PI的多样性与之前研究的三个基因进行比较，揭示了拟南芥核基因座之间常见的核苷酸多态性模式中的几个特征，包括低频核苷酸多态性过多以及种内替换变异水平显著升高。这种模式表明，拟南芥最近经历了快速的种群扩张，现在存在于小的、自交的亚种群中。因此，种内替换水平的升高可能代表了区分不同生态型的轻微有害多态性。AP3和PI核心及非核心功能域中替换和同义变化的分布也表明了这些相互作用的花调控基因之间分子进化模式的差异。
