Hayasaki M, Morikawa T, Leggett J M
Graduate School of Agriculture and Biological Sciences, Osaka Prefecture University, Sakai, Japan.
Genes Genet Syst. 2001 Feb;76(1):9-14. doi: 10.1266/ggs.76.9.
The tetraploid species Avena agadiriana that was first described in 1985 is distributed on the Atlantic coastal strip south of Casablanca in Morocco. Five accessions of this species (M55, M59, M60, M71 and M74) were compared by using FISH and RFLP analysis of 18S-5.8S-26S rDNA. The FISH data indicated that three pairs of major hybridization sites of the rDNA were located on satellite chromosomes in accessions M55, M59, M60 and M71. Accession M74, however, had only two pairs of major sites of hybridization. A pair of the major rDNA sites in M71 was very small and closely located at the terminal region of Nor-ST (Nucleolar organizing region of subtelocentrics) chromosomes. RFLP analysis of the rDNA sequence fragments identified differences among M55, M71 and M74, whilst M59 and M60 were the same with regard to the four restriction enzyme fragments utilized. M74 always lost single rDNA fragments in four restriction enzyme digests. The RFLP data made it possible to distinguish M55 from M59 and M60 in the northern Haut-Atlas Mountains group. A unique 20 kb EcoRI fragment characterized M71. Thus, a combination of FISH and RFLP analysis of rDNA was a good tool for inferring intraspecific evolutionary relationship of A. agadiriana.
四倍体物种阿加迪尔燕麦（Avena agadiriana）于1985年首次被描述，分布在摩洛哥卡萨布兰卡以南的大西洋沿岸地带。利用18S - 5.8S - 26S rDNA的荧光原位杂交（FISH）和限制性片段长度多态性（RFLP）分析，对该物种的5份材料（M55、M59、M60、M71和M74）进行了比较。FISH数据表明，rDNA的三对主要杂交位点位于材料M55、M59、M60和M71的随体染色体上。然而，材料M74只有两对主要杂交位点。M71中的一对主要rDNA位点非常小，紧密位于近端着丝粒染色体的核仁组织区（Nor - ST）的末端区域。对rDNA序列片段的RFLP分析确定了M55、M71和M74之间的差异，而对于所使用的四种限制酶片段，M59和M60是相同的。在四种限制酶消化中，M74总是丢失单个rDNA片段。RFLP数据使得在北高阿特拉斯山脉组中区分M55与M59和M60成为可能。一个独特的20 kb EcoRI片段是M71的特征。因此，rDNA的FISH和RFLP分析相结合是推断阿加迪尔燕麦种内进化关系的良好工具。
