Department of Anatomy and Developmental Biology, Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
Dev Dyn. 2021 Sep;250(9):1248-1263. doi: 10.1002/dvdy.288. Epub 2021 Jan 11.
The vertebrate limb is a dynamic structure which has evolved into many diverse forms to facilitate complex behavioral adaptations. The principle molecular and cellular processes that underlie development of the vertebrate limb are well characterized. However, how these processes are altered to drive differential limb development between vertebrates is less well understood. Several vertebrate models are being utilized to determine the developmental basis of differential limb morphogenesis, though these typically focus on later patterning of the established limb bud and may not represent the complete developmental trajectory. Particularly, heterochronic limb development can occur prior to limb outgrowth and patterning but receives little attention. This review summarizes the genetic regulation of vertebrate forelimb diversity, with particular focus on wing reduction in the flightless emu as a model for examining limb heterochrony. These studies highlight that wing reduction is complex, with heterochronic cellular and genetic events influencing the major stages of limb development. Together, these studies provide a broader picture of how different limb morphologies may be established during development.
脊椎动物的肢体是一种动态结构，已经进化出多种不同的形式，以促进复杂的行为适应。脊椎动物肢体发育的主要分子和细胞过程已经得到很好的描述。然而，这些过程是如何被改变的，以驱动脊椎动物之间不同的肢体发育，还不太清楚。目前正在利用几种脊椎动物模型来确定差异肢体形态发生的发育基础，尽管这些模型通常侧重于已建立的肢体芽的后期模式形成，而可能不能代表完整的发育轨迹。特别是，肢体发育的异时性可能发生在肢体生长和模式形成之前，但很少受到关注。这篇综述总结了脊椎动物前肢多样性的遗传调控，特别关注无翼鸵鸟翅膀退化作为研究肢体异时性的模型。这些研究表明，翅膀退化是复杂的，异时性的细胞和遗传事件影响肢体发育的主要阶段。总之，这些研究提供了一个更广泛的图景，说明在发育过程中如何建立不同的肢体形态。
