中文摘要：

裸子植物是一类种子裸露的植物,包括松杉类、苏铁类、银杏类和倪藤类,它们的进化历史悠久。核核糖体RNA基因（nrDNA）家族已作为一个重要的分子标记,用于推断很多分类等级上的系统发育关系。相对于被子植物中的快速致同进化,nrDNA在裸子植物中的致同进化速率低,且内转录间隔区ITS和5S非转录间隔区有着较大的长度变异,这种现象在松科植物中尤为明显。本文从基因的结构与功能、基因组内拷贝数、染色体定位与位点数变异、系统发育研究等四个方面对裸子植物nrRNA基因家族进化的研究作一综述。

英文摘要：

The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo and Gnetales,with a long evolutionary history. Nuclear ribosomal RNA gene （nrDNA） family has been considered an important tool for inferring phylogennetic relationships at many taxonomic levels. In comparison with its fast concerted evolution in angiosperms, nrDNA is symbolized by slow concerted evolution and substantial ITS region length variation in gymnosperms, particularly in Pinaceae. Gene structure and functions, number of copies, loci distribution and number of sites in chromosomes, and phylogenetic implications of nrDNA in gymnosperms are reviewed in this paper.