Laboratory of Chromosome Studies, Department of Structural and Functional Biology, Institute of Biology, University of Campinas, Campinas 13083-863, SP, Brazil.
Department of Zoology, Institute of Biological Sciences, Federal University of Minas Gerais, Belo Horizonte 31270-901, MG, Brazil.
Genes (Basel). 2019 Feb 19;10(2):160. doi: 10.3390/genes10020160.
In the frog genus , previous works found a sex-linked heteromorphism of the PcP190 satellite DNA in the nucleolus organizer region (NOR)-bearing chromosome pairs of and , which possess a ZZ/ZW sex determination system. A pericentromeric inversion was inferred to have occurred during W chromosome evolution, moving a chromosomal cluster enriched by the PcP190 from the short arm (as observed in ) to the NOR-bearing long arm (as observed in ). However, whether such an inversion happened in or in the common ancestor of and remained unclear. To assess this question, we mapped PcP190 in the karyotype of from three distinct localities. Southern blotting was used to compare males and females. The mitochondrial H1 fragment (which contains the 12S ribosomal RNA (rRNA), tRNAval, and 16S rRNA genes) and cytochrome b gene were partially sequenced, and a species tree was inferred to guide our analysis. specimens were placed together as the sister group of , but based on genetic distance, one of the analyzed populations is probably an undescribed species. A cluster of PcP190, located in the long arm of chromosome 7, is sex linked in this putative new species but not in the remaining . We could infer that the pericentromeric inversion that moved the PcP190 site to the NOR-bearing chromosome arm (long arm) occurred in the common ancestor of , the putative undescribed species, and .
在蛙属中,之前的研究发现,具有 ZZ/ZW 性别决定系统的 和 染色体对的核仁组织者区域(NOR)携带的 PcP190 卫星 DNA 存在性连锁异态性。推断在 W 染色体进化过程中发生了着丝粒周围倒位,将 PcP190 富集的染色体簇从短臂(如 在 中观察到的)移动到 NOR 携带的长臂(如 在 中观察到的)。然而,这种倒位是在 中发生的,还是在 和 的共同祖先中发生的,尚不清楚。为了评估这个问题,我们在来自三个不同地点的 的核型中定位了 PcP190。Southern 印迹用于比较雄性和雌性。线粒体 H1 片段(包含 12S 核糖体 RNA(rRNA)、tRNAval 和 16S rRNA 基因)和细胞色素 b 基因部分测序,并推断种系发生树来指导我们的分析。 标本与 一起被放置为姐妹群,但基于遗传距离,其中一个分析的种群可能是一个未描述的物种。位于染色体 7 长臂上的 PcP190 簇在这个假定的新物种中是性连锁的,但在其余的 中不是。我们可以推断,将 PcP190 位点移动到 NOR 携带染色体臂(长臂)的着丝粒周围倒位发生在 、假定的未描述物种和 的共同祖先中。