Verma M, Dutta S K
Department of Botany, Howard University, Washington, DC 20059.
Curr Genet. 1987;11(4):309-14. doi: 10.1007/BF00355405.
Nontranscribed spacer (NTS) regions of ribosomal (r)RNA genes are non-conserved and are shown to be useful for phylogenetic studies. 32P-labelled N. crassa NTS pCC3400 DNA, was used as a molecular probe to hybridize Southern blots of genomic DNAs obtained from Neurospora, Gelacinospora, Sordaria, bacteria, plants, and animals. Our studies conclude that: (a) the homotahllic species of Neurospora should not belong to genus Gelacinospora (a historical question) and that Neurospora homothallic species are closer to Gelacinospora than to Sordaria; and that (b) all of the filamentous fungal species tested are indeed closer to the higher plant genome than to higher primate animal genome based on shared restriction sites of 12 enzymes. Our studies also demonstrate the usefulness of nontranscribed rRNA gene probes in resolving questions regarding phylogenetic relatedness between widely separated organisms using the parsimony principle based on mutation sites from DNA restriction maps; it has not been possible to do this using DNA: DNA hybridization procedures that involved the total genome.
核糖体（r）RNA基因的非转录间隔区（NTS）是不保守的，已证明其在系统发育研究中很有用。用32P标记的粗糙脉孢菌NTS pCC3400 DNA作为分子探针，与从脉孢菌属、胶孢菌属、粪壳菌属、细菌、植物和动物获得的基因组DNA的Southern杂交印迹进行杂交。我们的研究得出以下结论：（a）脉孢菌属的同宗配合物种不应属于胶孢菌属（一个历史问题），并且脉孢菌属的同宗配合物种与胶孢菌属的亲缘关系比与粪壳菌属更近；以及（b）基于12种酶的共享限制位点，所有测试的丝状真菌物种确实与高等植物基因组的亲缘关系比与高等灵长类动物基因组更近。我们的研究还证明了非转录rRNA基因探针在使用基于DNA限制图谱突变位点的简约原则解决广泛分离的生物体之间系统发育相关性问题方面的有用性；使用涉及全基因组的DNA:DNA杂交程序无法做到这一点。
