摘要
绵枣儿是分布在东亚的多倍体复合体。以Giemsa-C带法对分布在中国的绵枣儿24个居群进行了染色体变异分析。AA和BB细胞型大部分居群未发现变异,分别具a2和b1染色体的近着丝点着丝粒带。AABB虽无居群内变异,但居群间有所不同。其中柳林、商南和徐州居群带型相同,带纹丰富。元宝山居群只有b1的近着丝粒带,而灵岩山居群具a2和b1的近着丝粒带。根据已有的研究资料推测,绵枣儿b1和a2上的近着丝粒带显示的应当是高度重复的rRNA基因;大庆和文县居群一个体该位点的杂合可能是由于部分rRNA拷贝的同源染色体间转移;AABB起源后随时间推移会发生rRNA重复位点的丢失;柳林等居群丰富的带纹可能是其刚刚起源时重复基因关闭的表征,随时间推移同样可能会丢失。另外大量的实验证据表明,BB比AA细胞型可能更易于发生染色体结构变异。
Barnardia japonica Thunb.is a polypliod complex occupying East Asia,and the chromosome variation was analyzed by the Giemsa-C banding method for 24 populations of this complex.No variation was found in Giemsa-C banding between and within the most populations of AA and BB cytotypes and subcentromeric bands present on a2 chromosomes in AA cytotype and b1 in BB.There is no variation within each of the tested populations in AABB cytotype,but there is between the populations.AABB populations in Central China have the same and abundant Giemsa-C bands,but only b1 chromosomes have subcentrimeric bands in Population Yuanbaoshan,and only a2 and b1 have subcentrimeric bands in Population Lingyanshan.It is concluded that subcentrimeric bands on the a2 and b1 are possibly rRNA genes and heterozygosity at this chromosomal region of individuals in Populations Daqing and Wenxian may be due to shift of its some copies between homologous chromosomes;Abundance in Giemsa-C bands in populations in Central China is probably reflections of the depression of some duplicated genes at the beginning of its origin,and this complicated DNA probably was deleted during the evolution of this new tetrapolyploid;Chromosomal structure changes more easier in BB than in AA cytotype.
出处
《武汉植物学研究》
CSCD
北大核心
2007年第5期421-426,共6页
Journal of Wuhan Botanical Research
基金
国家自然科学基金资助项目(30270095)
