Institute of Molecular and Cellular Biology SB RAS, Lavrentiev Ave., 8/2, 630090 Novosibirsk, Russia.
Department of Ichthyology and Hydrobiology, Tomsk State University, Lenin Ave, 36, 634050 Tomsk, Russia.
Genes (Basel). 2020 Nov 20;11(11):1375. doi: 10.3390/genes11111375.
Polyploid genomes present a challenge for cytogenetic and genomic studies, due to the high number of similar size chromosomes and the simultaneous presence of hardly distinguishable paralogous elements. The karyotype of the Siberian sturgeon () contains around 250 chromosomes and is remarkable for the presence of paralogs from two rounds of whole-genome duplications (WGD). In this study, we applied the sterlet-derived acipenserid satDNA-based whole chromosome-specific probes to analyze the Siberian sturgeon karyotype. We demonstrate that the last genome duplication event in the Siberian sturgeon was accompanied by the simultaneous expansion of several repetitive DNA families. Some of the repetitive probes serve as good cytogenetic markers distinguishing paralogous chromosomes and detecting ancestral syntenic regions, which underwent fusions and fissions. The tendency of minisatellite specificity for chromosome size groups previously observed in the sterlet genome is also visible in the Siberian sturgeon. We provide an initial physical chromosome map of the Siberian sturgeon genome supported by molecular markers. The application of these data will facilitate genomic studies in other recent polyploid sturgeon species.
多倍体基因组为细胞遗传学和基因组研究带来了挑战，这是由于大量相似大小的染色体和难以区分的同源基因同时存在。西伯利亚鲟的核型包含约 250 条染色体，其特点是存在两轮全基因组复制（WGD）的同源基因。在这项研究中，我们应用了从施氏鲟获得的基于 acipenserid satDNA 的整条染色体特异性探针来分析西伯利亚鲟的核型。我们证明，西伯利亚鲟的最后一次基因组复制事件伴随着几个重复 DNA 家族的同时扩张。一些重复探针可用作良好的细胞遗传学标记，区分同源染色体并检测经历融合和裂变的祖先同线性区域。在施氏鲟基因组中观察到的小卫星特异性与染色体大小群之间的关系在西伯利亚鲟中也可见。我们提供了由分子标记支持的西伯利亚鲟基因组的初步物理染色体图谱。这些数据的应用将有助于其他近期多倍体鲟鱼物种的基因组研究。
