Department of Biology, Technion - Israel Institute of Technology, Haifa 32000, Israel.
Dev Cell. 2011 Apr 19;20(4):483-96. doi: 10.1016/j.devcel.2011.03.015.
Changes in gene expression are thought to be important for morphological evolution, though little is known about the nature or magnitude of the differences. Here, we examine Xenopus laevis and Xenopus tropicalis, two amphibians with very similar development, and ask how their transcriptomes compare. Despite separation for ~30-90 million years, there is strong conservation in gene expression in the vast majority of the expressed orthologs. Significant changes occur in the level of gene expression but changes in the timing of expression (heterochrony) were much less common. Differences in level were concentrated in the earliest embryonic stages. Changes in timing were prominently found in pathways that respond to selective features of the environment. We propose that different evolutionary rates across developmental stages may be explained by the stabilization of cell fate determination in the later stages.
基因表达的变化被认为对形态进化很重要，但对于差异的性质或程度知之甚少。在这里，我们研究了两种发育非常相似的两栖动物——非洲爪蟾和热带爪蟾，探讨了它们的转录组有何不同。尽管已经分离了大约 3000 万到 9000 万年，但绝大多数表达的直系同源基因的表达仍然具有很强的保守性。基因表达水平发生了显著变化，但表达的时间（异时性）变化则要少见得多。水平上的差异主要集中在最早的胚胎阶段。在对环境的选择特征做出反应的途径中，发现了时间变化的显著差异。我们提出，不同的发育阶段的进化速度可能可以用晚期细胞命运决定的稳定性来解释。
