Genome. 1995 Feb;38(1):91-6. doi: 10.1139/g95-011.
An accurate physical map of the location of the 5S and the 18S-5.8S-25S rRNA genes and a repetitive DNA sequence has been produced on Aegilops umbellulata Zhuk., (2n = 2x = 14) chromosomes by in situ hybridization. Chromosome morphology together with the hybridization pattern of pSc119.2, a DNA sequence from rye, allowed identification and discrimination of different chromosomes; pSc119.2 hybridizes with all Ae. umbellulata chromosomes at the telomeres, except for the short arm of chromosome 6U, and shows intercalary sites on the long arms of chromosomes 6U and 7U. The 5S and 18S-25S rDNA have been mapped physically only on the short arms of chromosomes 1U and 5U. On chromosome 1U the order of the genes is 5S rDNA subterminal and 18S-25S rDNA more proximal, while on chromosome 5U the position of the genes is reversed. The relative order of the genes, together with the hybridization pattern of the pSc119.2, is useful in identifying whole chromosomes or chromosome segments from Ae. umbellulata in recombinant or addition lines with wheat. The data help link the physical organization of chromosomes to the genetic map. Other members of the Triticeae vary in the presence and order of the 5S and 18S-25S rDNA sequences on groups 1 and 5, indicating multiple and complex evolutionary rearrangements of the chromosome arms.
通过原位杂交，已经在节节麦（2n = 2x = 14）染色体上生成了 5S 和 18S-5.8S-25S rRNA 基因和重复 DNA 序列的准确物理图谱。染色体形态以及来自黑麦的 DNA 序列 pSc119.2 的杂交模式允许鉴定和区分不同的染色体；pSc119.2 在端粒处与所有节节麦染色体杂交，但 6U 染色体的短臂除外，并且在 6U 和 7U 染色体的长臂上显示插入位点。5S 和 18S-25S rDNA 仅在 1U 和 5U 染色体的短臂上进行了物理作图。在染色体 1U 上，基因的顺序为 5S rDNA 亚末端和 18S-25S rDNA 更接近，而在染色体 5U 上基因的位置则相反。基因的相对顺序以及 pSc119.2 的杂交模式有助于识别带有小麦的重组或添加系中来自节节麦的整条染色体或染色体片段。这些数据有助于将染色体的物理组织与遗传图谱联系起来。三属植物的其他成员在第 1 组和第 5 组上的 5S 和 18S-25S rDNA 序列的存在和顺序上存在差异，这表明染色体臂发生了多次复杂的进化重排。
