Liu Ya, Song Menghuan, Luo Wei, Xia Yun, Zeng Xiaomao
Cytogenet Genome Res. 2019;157(3):172-178. doi: 10.1159/000499416. Epub 2019 Apr 6.
In an attempt to analyze the organization of repetitive DNAs in the amphibian genome, 7 microsatellite motifs and a 5S rDNA sequence were synthesized and mapped in the karyotypes of 5 Amolops species. The results revealed nonrandom distribution of the microsatellite repeats, usually in the heterochromatic regions, as found in other organisms. These microsatellite repeats showed rapid changes among Amolops species, documenting the recent evolutionary history within this lineage. In contrast, 5S rDNA was localized in chromosomes 5 of all species, suggesting that these chromosomes are homologous within the monophyletic clade. Furthermore, the heteromorphic X and Y sex chromosomes (chromosomes 5) of A.mantzorum, had identical patterns of 5S rDNA, indicating that the subtelocentric Y resulted from a pericentric inversion. Several microsatellite repeats were found in the heteromorphic sex chromosomes, verifying the association of repetitive DNAs with sex chromosome differentiation in A. mantzorum.
为了分析两栖动物基因组中重复DNA的组织情况，合成了7个微卫星基序和一个5S rDNA序列，并将其定位到5种湍蛙属物种的核型中。结果显示，微卫星重复序列呈非随机分布，通常位于异染色质区域，这与其他生物的情况一致。这些微卫星重复序列在湍蛙属物种间变化迅速，记录了该谱系最近的进化历史。相比之下，5S rDNA定位于所有物种的第5号染色体上，表明这些染色体在单系类群中是同源的。此外，滇南湍蛙异形的X和Y性染色体（第5号染色体）具有相同的5S rDNA模式，表明亚端部着丝粒的Y染色体是由臂间倒位产生的。在异形性染色体中发现了几个微卫星重复序列，证实了重复DNA与滇南湍蛙性染色体分化之间的关联。
