Department of Genetics and Microbiology, University of Bari, 70126 Bari, Italy.
Genome Res. 2012 Dec;22(12):2520-8. doi: 10.1101/gr.138651.112. Epub 2012 Aug 14.
Chromosome rearrangements in small apes are up to 20 times more frequent than in most mammals. Because of their complexity, the full extent of chromosome evolution in these hominoids is not yet fully documented. However, previous work with array painting, BAC-FISH, and selective sequencing in two of the four karyomorphs has shown that high-resolution methods can precisely define chromosome breakpoints and map the complex flow of evolutionary chromosome rearrangements. Here we use these tools to precisely define the rearrangements that have occurred in the remaining two karyomorphs, genera Symphalangus (2n = 50) and Hoolock (2n = 38). This research provides the most comprehensive insight into the evolutionary origins of chromosome rearrangements involved in transforming small apes genome. Bioinformatics analyses of the human-gibbon synteny breakpoints revealed association with transposable elements and segmental duplications, providing some insight into the mechanisms that might have promoted rearrangements in small apes. In the near future, the comparison of gibbon genome sequences will provide novel insights to test hypotheses concerning the mechanisms of chromosome evolution. The precise definition of synteny block boundaries and orientation, chromosomal fusions, and centromere repositioning events presented here will facilitate genome sequence assembly for these close relatives of humans.
小型猿类的染色体重排频率比大多数哺乳动物高 20 倍。由于其复杂性，这些人科动物的染色体进化的全貌尚未完全记录下来。然而，之前使用微阵列杂交、BAC-FISH 和两种核型中的两种选择性测序的研究表明，高分辨率方法可以精确定义染色体断裂点，并绘制出进化过程中复杂的染色体重排流。在这里，我们使用这些工具精确地定义了其余两种核型中发生的重排，即 Symphalangus（2n = 50）和 Hoolock（2n = 38）属。这项研究为我们深入了解参与改造小型猿类基因组的染色体重排的进化起源提供了最全面的认识。对人类-长臂猿同线性断点的生物信息学分析表明，这些断点与转座元件和片段重复有关，这为可能促进小型猿类发生重排的机制提供了一些线索。在不久的将来，对长臂猿基因组序列的比较将提供新的见解，以检验关于染色体进化机制的假设。这里提出的同线性块边界和方向、染色体融合和着丝粒重定位事件的精确定义将为这些人类的近亲的基因组序列组装提供便利。
