Gibbon genome and the fast karyotype evolution of small apes

摘要

本期封面上是一只5个月大的雌性北方白颊长臂猿（Nomascus leucogenys),名叫"辣椒"。很多种长臂猿都是来自东南亚的小型树栖猿类,其中大多数都被世界自然保护联盟(IUCN)列为"濒危"或"极度濒危"物种。Lucia Carbone及同事在其所发表的关于白颊长臂猿基因组的论文中，提供了关于这样一个介于"旧世界"猴子与类人猿之间的物种类别的生物学和进化史的有趣信息。作者对一个长臂猿特有的反转录转座子何以有可能成为长臂猿基因组可塑性之源进行了研究。迅速的核型演化结合多次气候和环境变化，也许可解释四个长臂猿属几乎瞬时发生的分化。对涉及前肢发育和结缔组织的基因的选择，也许与长臂猿在热带林冠中独特的运动方式有关。封面: Gabriella Skollar 2011年7月摄于美国加州圣克拉里塔的长臂猿保护中心。%Gibbons are small arboreal apes that display an accelerated rate of evolutionary chromosomal rearrangement and occupy a key node in the primate phytogeny between Old World monkeys and great apes. Here we present the assembly and analysis of a northern white-cheeked gibbon (Nomascus leucogenys) genome. We describe the propensity for a gibbon-specific retrotransposon (LAVA) to insert into chromosome segregation genes and alter transcription by providing a premature termination site, suggesting a possible molecular mechanism for the genome plasticity of the gibbon lineage. We further show that the gibbon genera (Nomascus, Hylobates, Hoolock and Symphalangus) experienced a near-instantaneous radiation ～5 million years ago, coincident with major geographical changes in southeast Asia that caused cycles of habitat compression and expansion. Finally, we identify signatures of positive selection in genes important for forelimb development (TBX5) and connective tissues (COL1A1) that may have been involved in the adaptation of gibbons to their arboreal habitat.