Genome. 1993 Dec;36(6):1015-22. doi: 10.1139/g93-135.
In situ DNA hybridization with 18S-28S and 5S ribosomal DNA probes was used to map 18S-28S nucleolar organizers and tandem 5S repeats to meiotic chromosomes of cotton (Gossypium hirsutum L.). Mapping was performed by correlating hybridization sites to particular positions in translocation quadrivalents. Arm assignment required translocation quadrivalents with at least one interstitial chiasma and sufficient distance between the hybridization site and the centromere. We had previously localized a major 18S-28S site to the short arm of chromosome 9; here we mapped two additional major 18S-28S sites to the short arm of chromosome 16 and the left arm of chromosome 23. We also identified and mapped a minor 18S-28S site to the short arm of chromosome 7. Two 5S sites of unequal size were identified, the larger one near the centromere of chromosome 9 and the smaller one near the centromere of chromosome 23. Synteny of 5S and 18S-28S sites indicated homeology of chromosomes 9 and 23, while positions of the other two 18S-28S sites supplement genetic evidence that chromosomes 7 and 16 are homeologous.
原位杂交使用 18S-28S 和 5S 核糖体 DNA 探针，以定位棉（Gossypium hirsutum L.）减数分裂染色体中的 18S-28S 核仁组织者和串联 5S 重复序列。通过将杂交位点与易位四价体中的特定位置相关联来进行作图。臂的分配需要具有至少一个间质交叉的易位四价体，以及杂交位点和着丝粒之间有足够的距离。我们之前已经将主要的 18S-28S 位点定位到染色体 9 的短臂上；在这里，我们将另外两个主要的 18S-28S 位点定位到染色体 16 的短臂和染色体 23 的左臂上。我们还鉴定并定位了一个次要的 18S-28S 位点到染色体 7 的短臂上。鉴定到两个大小不等的 5S 位点，较大的一个位于染色体 9 的着丝粒附近，较小的一个位于染色体 23 的着丝粒附近。5S 和 18S-28S 位点的同线性表明染色体 9 和 23 的同源性，而其他两个 18S-28S 位点的位置补充了遗传证据，表明染色体 7 和 16 是同源的。
