Stanton D J, Daehler L L, Moritz C C, Brown W M
Department of Biology and Museum of Zoology, University of Michigan, Ann Arbor 48109-1048.
Genetics. 1994 May;137(1):233-41. doi: 10.1093/genetics/137.1.233.
Tandem duplications of gene-encoding regions occur in the mitochondrial DNA (mt DNA) of some individuals belonging to several species of whiptail lizards (genus Cnemidophorus). All or part of the duplicated regions of the mtDNAs from five different species were sequenced. In all, the duplication endpoints were within or immediately adjacent to sequences in tRNA, rRNA or protein genes that are capable of forming energetically stable stem-and-loop structures. In two of these mtDNAs, the duplication endpoints were also associated with a direct sequence repeat of 13 bp. The consistent association of stem-and-loop structures with duplication endpoints suggests that these structures may play a role in the duplication process. These data, combined with the absence of direct or palindromic repeats at three of the pairs of duplication endpoints, also suggest the existence of a mechanism for generating de novo duplications that is qualitatively different from those previously modeled.
编码基因区域的串联重复出现在几种鞭尾蜥蜴(鞭尾蜥属)的一些个体的线粒体DNA(mtDNA)中。对来自五个不同物种的mtDNA的全部或部分重复区域进行了测序。总体而言,重复端点位于能够形成能量稳定的茎环结构的tRNA、rRNA或蛋白质基因的序列内或紧邻其序列。在其中两个mtDNA中,重复端点还与一个13bp的直接序列重复相关。茎环结构与重复端点的一致关联表明这些结构可能在重复过程中发挥作用。这些数据,再加上在三对重复端点处不存在直接或回文重复,也表明存在一种与先前模型在性质上不同的从头重复生成机制。