Busch W, Martin R, Herrmann R G, Hohmann U
Botanisches Institut, Ludwig-Maximilians-Universität München, Germany.
Genome. 1995 Dec;38(6):1082-90. doi: 10.1139/g95-144.
We report on microdissection, cloning and sequence, and Southern and fluorescence in situ hybridization (FISH) analysis of one moderately and one highly amplified repetitive DNA element, pHvMWG2314 and pHvMWG2315, respectively, isolated from barley (Hordeum vulgare L.) chromosome arm 3HL. The pHvMWG2315 sequence hybridizes to all 14 telomeric or subtelomeric regions of the barley chromosomes as determined by FISH. The 50 different hybridization sites that include intercalary signals allow the discrimination of all 14 chromosome arms and the construction of a kariotype of barley. The tandemly repeated subtelomeric element of 331 bp exists in all Triticeae species tested (H. vulgare, Agropyron elongatum, Secale cereale, Triticum tauschii, T. turgidum, and T. aestivum). It is AT rich (66%), exibits 84% sequence homology to subfragments of the D genome ¿specific¿ 1-kb element pAs1 of T. tauscii and 75% homology to interspersed genome-specific DNA sequence pHcKB6 from H. chilence. The repetitive sequence pHvMWG2314 is moderately amplified in barley and highly amplified in hexaploid wheat. The in situ experiments revealed no distinct signals on barley chromosomes, indicating a dispersed character for the sequence. The significance of the results for the identification of chromosomes and chromosome aberrations in FISH experiments are discussed.
我们报告了从大麦（Hordeum vulgare L.）3HL染色体臂分离的两个重复DNA元件pHvMWG2314和pHvMWG2315的显微切割、克隆与测序，以及Southern杂交和荧光原位杂交（FISH）分析，其中一个为中度扩增，另一个为高度扩增。通过FISH确定，pHvMWG2315序列与大麦染色体的所有14个端粒或亚端粒区域杂交。50个不同的杂交位点包括居间信号，可区分所有14条染色体臂并构建大麦核型。331 bp的串联重复亚端粒元件存在于所有测试的小麦族物种（大麦、长穗偃麦草、黑麦、节节麦、硬粒小麦和普通小麦）中。它富含AT（66%），与节节麦D基因组“特异性”1 kb元件pAs1的亚片段具有84%的序列同源性，与来自智利大麦的散布基因组特异性DNA序列pHcKB6具有75%的同源性。重复序列pHvMWG2314在大麦中中度扩增，在六倍体小麦中高度扩增。原位实验显示大麦染色体上没有明显信号，表明该序列具有分散性。讨论了这些结果在FISH实验中鉴定染色体和染色体畸变的意义。
