Hariharan Iswar K, Wake David B, Wake Marvalee H
Department of Molecular and Cell Biology, University of California, Berkeley, California 94720.
Department of Integrative Biology, University of California, Berkeley, California 94720.
Cold Spring Harb Perspect Biol. 2015 Jul 27;8(2):a019174. doi: 10.1101/cshperspect.a019174.
Although we are used to the idea that many organisms stop growing when they reach a predictable size, in many taxa, growth occurs throughout the life of an organism, a phenomenon referred to as indeterminate growth. Our comparative analysis suggests that indeterminate growth may indeed represent the ancestral condition, whereas the permanent arrest of growth may be a more derived state. Consistent with this idea, in diverse taxa, the basal branches show indeterminate growth, whereas more derived branches arrest their growth. Importantly, in some closely related taxa, the termination of growth has evolved in mechanistically distinct ways. Also, even within a single organism, different organs can differ with respect to whether they terminate their growth or not. Finally, the study of tooth development indicates that, even at the level of a single tissue, multiple determinate patterns of growth can evolve from an ancestral one that is indeterminate.
尽管我们习惯于这样的观点，即许多生物在达到可预测的大小时就会停止生长，但在许多分类群中，生物在其整个生命过程中都会生长，这种现象被称为无限生长。我们的比较分析表明，无限生长可能确实代表了祖先的状态，而生长的永久停止可能是一种更为衍生的状态。与此观点一致的是，在不同的分类群中，基部的分支表现出无限生长，而更为衍生的分支则停止生长。重要的是，在一些密切相关的分类群中，生长的终止以机械上不同的方式进化。此外，即使在单个生物体内，不同的器官在是否停止生长方面也可能存在差异。最后，牙齿发育的研究表明，即使在单个组织的层面上，多种确定的生长模式也可以从一种不确定的祖先模式进化而来。
