Homeobox Genes and Evolutionary Innovation

9507466 最近发现的基因控制的发展，动物的身体计划（同源异型盒基因）提供了一个机会，以解决一个最基本的问题，在生物学。 也就是说，是什么机制导致了生物多样性中主要辐射特征的新特征或身体计划的出现？ 我们知道物种是如何通过改变给定的身体结构来适应环境变化的，但我们还不知道一个特定的身体结构是如何首先存在的。 例如，青蛙与相关的两栖动物的不同之处在于有两个脚踝骨，大大延长，提高了跳跃能力。 这项研究将测试的假设，同源异型盒基因的表达变化导致了这种形态的创新。 它将研究青蛙肢体中基因的表达，在其他脊椎动物中，这些基因控制着小腿（长骨）和脚踝（通常是短骨）的分化。 研究结果将表明，在青蛙的踝关节骨伸长过程中，负责小腿伸长的基因是否活跃，而在其他脊椎动物中则不然。如果是这样的话，它将表明脊椎动物的特征可以通过改变一些发育控制基因的表达而经历重大的进化变化。这些结果可以增加对遗传机制和进化历史的理解，并解释化石记录中某些形态创新的快速出现。

9507466 The recent discovery of genes controlling the development of the animal body plan (homeobox genes) provides an opportunity to address one of the most fundamental questions in biology. That is, what mechanisms have led to the appearance of new characters or body plans that characterize major radiations in biological diversity? We understand how species adapt to environmental changes by modifying a given body plan, but we do not yet understand how a particular body plan came into existence in the first place. For example, frogs differ from related amphibians in having two ankle bones that are greatly elongated, improving jumping ability. This research will test the hypothesis that changes in expression of homeobox genes led to this morphological innovation. It will study the expression of genes in the frog limb that, in other vertebrates, control the differentiation into lower leg (long bones) and ankle (usually short bones). The results will show whether the gene responsible for lower leg elongation is active during elongation of the ankle bones of frogs, but not in other vertebrates. If so, it will show that a vertebrate character can undergo a major evolutionary change via alteration in the expression of a few developmental control genes. The results could increase understanding of genetic mechanisms, of evolutionary history and account for the rapid appearance of certain morphological innovations in the fossil record.