Institute of Biophysics, Academy of Sciences of the Czech Republic, Královopolská 135, 612 65, Brno, Czech Republic.
Theor Appl Genet. 1996 Jun;92(8):1108-11. doi: 10.1007/BF00224057.
In order to investigate possible interactions between parental genomes in the composite genome of Nicotiana tabacum we have analyzed the organization of telomeric (TTTAGGG)n and ribosomal gene (rDNA) repeats in the progenitor genomes Nicotiana sylvestris and Nicotiana tomentosiformis or Nicotiana otophora. Telomeric arrays in the Nicotiana species tested are heterogeneous in length ranging from 20 to 200 kb in N. sylvestris, from 20 to 50 kb in N. tomentosiformis, from 15 to 100kb in N. otophora, and from 40 to 160kb in N. tabacum. The patterns of rDNA repeats (18S, 5.8S, 25S RNA) appeared to be highly homogeneous and speciesspecific; no parental rDNA units corresponding to N. sylvestris, N. tomentosiformis or N. otophora were found in the genome of N. tabacum by Southern hybridization. The results provide evidence for a species-specific evolution of telomeric and ribosomal repeats in the tobacco composite genome.
为了研究烟草原生基因组在复合基因组中的双亲基因组之间可能存在的相互作用，我们分析了亲本基因组烟草野烟和黄花烟草或拟南芥烟草中端粒（TTTAGGG）n 和核糖体基因（rDNA）重复序列的组织。在测试的烟草物种中，端粒阵列的长度不均一，N. sylvestris 中的端粒长度为 20 到 200kb，N. tomentosiformis 中的端粒长度为 20 到 50kb，N. otophora 中的端粒长度为 15 到 100kb，N. tabacum 中的端粒长度为 40 到 160kb。rDNA 重复序列（18S、5.8S、25S RNA）的模式似乎高度同源且具有物种特异性；通过 Southern 杂交，在 N. tabacum 基因组中未发现与 N. sylvestris、N. tomentosiformis 或 N. otophora 相对应的亲本 rDNA 单位。这些结果为烟草复合基因组中端粒和核糖体重复序列的物种特异性进化提供了证据。
