Sears Karen, Maier Jennifer A, Sadier Alexa, Sorensen Daniel, Urban Daniel J
Department of Ecology and Evolutionary Biology, University of California at Los Angeles, Los Angeles, California, 90095.
Lillehei Heart Institute, University of Minnesota, Minneapolis, Minnesota, 55455.
Genesis. 2018 Jan;56(1). doi: 10.1002/dvg.23079. Epub 2017 Nov 2.
Mammals have highly diverse limbs that have contributed to their occupation of almost every niche. Researchers have long been investigating the development of these diverse limbs, with the goals of identifying developmental processes and potential biases that shape mammalian limb diversity. To date, researchers have used techniques ranging from the genomic to the anatomic to investigate the developmental processes shaping the limb morphology of mammals from five orders (Marsupialia, Chiroptera, Rodentia, Cetartiodactyla, and Perissodactyla). Results of these studies suggest that the differential expression of genes controlling diverse cellular processes underlies mammalian limb diversity. Results also suggest that the earliest development of the limb tends to be conserved among mammalian species, while later limb development tends to be more variable. This research has established the mammalian limb as a model system for evolutionary developmental biology, and set the stage for more in-depth, cross-disciplinary research into the genetic controls, tissue-level cellular behaviors, and selective pressures that have driven the developmental evolution of mammalian limbs. Ideally, these studies will be performed in a diverse suite of mammalian species within a comparative, phylogenetic framework.
哺乳动物拥有高度多样的肢体，这使得它们能够占据几乎每一个生态位。长期以来，研究人员一直在研究这些多样肢体的发育情况，目的是确定塑造哺乳动物肢体多样性的发育过程和潜在偏差。迄今为止，研究人员已运用从基因组学到解剖学等各种技术，来研究塑造来自五个目（有袋目、翼手目、啮齿目、鲸偶蹄目和奇蹄目）哺乳动物肢体形态的发育过程。这些研究结果表明，控制多种细胞过程的基因的差异表达是哺乳动物肢体多样性的基础。结果还表明，肢体的早期发育在哺乳动物物种中往往是保守的，而后期肢体发育则往往更具变异性。这项研究已将哺乳动物肢体确立为进化发育生物学的一个模型系统，并为更深入的跨学科研究奠定了基础，这些研究涉及驱动哺乳动物肢体发育进化的遗传控制、组织水平的细胞行为和选择压力。理想情况下，这些研究将在比较系统发育框架内的一系列多样的哺乳动物物种中进行。
