Moustakas Jacqueline E
Department of Integrative Biology and Museum of Paleontology, University of California, 1101 Valley Life Sciences Building, Berkeley, CA 94720, USA.
Evol Dev. 2008 Jan-Feb;10(1):29-36. doi: 10.1111/j.1525-142X.2007.00210.x.
Paleontologists and neontologists have long looked to development to understand the homologies of the dermal bones that form the "armor" of turtles, crocodiles, armadillos, and other vertebrates. This study shows molecular evidence supporting a dermomyotomal identity for the mesenchyme of the turtle carapacial ridge. The mesenchyme of the carapace primordium expresses Pax3, Twist1, Dermo1, En1, Sim1, and Gremlin at early stages and before overt ossification expresses Pax1. A hypothesis is proposed that this mesenchyme forms dermal bone in the turtle carapace. A comparison of regulatory gene expression in the primordia of the turtle carapace, the vertebrate limb, and the vertebral column implies the exaptation of key genetic networks in the development of the turtle shell. This work establishes a new role for this mesodermal compartment and highlights the importance of changes in genetic regulation in the evolution of morphology.
古生物学家和现代生物学家长期以来一直通过研究发育过程来理解构成龟、鳄鱼、犰狳和其他脊椎动物“盔甲”的真皮骨的同源性。这项研究显示了分子证据，支持龟甲嵴间充质具有皮肌节特征。背甲原基的间充质在早期阶段表达Pax3、Twist1、Dermo1、En1、Sim1和Gremlin，在明显骨化之前表达Pax1。提出了一个假说，即这种间充质在龟的背甲中形成真皮骨。对龟背甲原基、脊椎动物肢体和脊柱中调控基因表达的比较表明，关键基因网络在龟壳发育过程中发生了适应性改变。这项工作确立了这个中胚层区域的新作用，并突出了基因调控变化在形态进化中的重要性。
