Griffing Aaron H, Gamble Tony, Cohn Martin J, Sanger Thomas J
Department of Biological Sciences, Marquette University, PO Box 1881, Milwaukee, WI 53201, USA.
Milwaukee Public Museum, 800 W. Wells St., Milwaukee, WI 53233, USA.
Biol J Linn Soc Lond. 2022 Jan 5;135(3):518-532. doi: 10.1093/biolinnean/blab164. eCollection 2022 Mar.
How developmental modifications produce key innovations, which subsequently allow for rapid diversification of a clade into new adaptive zones, has received much attention. However, few studies have used a robust comparative framework to investigate the influence of evolutionary and developmental constraints on the origin of key innovations, such as the adhesive toe pad of lizards. Adhesive toe pads evolved independently at least 16 times in lizards, allowing us to examine whether the patterns observed are general evolutionary phenomena or unique, lineage-specific events. We performed a high-resolution comparison of plantar scale development in 14 lizard species in and geckos, encompassing five independent origins of toe pads (one in , four in geckos). Despite substantial evolutionary divergence between and geckos, we find that these clades have undergone similar developmental modifications to generate their adhesive toe pads. Relative to the ancestral plantar scale development, in which scale ridges form synchronously along the digit, both padded geckos and exhibit scansor formation in a distal-to-proximal direction. Both clades have undergone developmental repatterning and, following their origin, modifications in toe pad morphology occurred through relatively minor developmental modifications, suggesting that developmental constraints governed the diversification of the adhesive toe pad in lizards.
发育修饰如何产生关键创新，进而使一个进化枝迅速多样化并进入新的适应区，这一问题已备受关注。然而，很少有研究使用强大的比较框架来探究进化和发育限制对关键创新起源的影响，比如蜥蜴的粘性趾垫。粘性趾垫在蜥蜴中至少独立进化了16次，这使我们能够检验所观察到的模式是普遍的进化现象还是独特的、特定谱系的事件。我们对14种蜥蜴和壁虎的足底鳞片发育进行了高分辨率比较，涵盖了趾垫的五个独立起源（蜥蜴中有一个，壁虎中有四个）。尽管蜥蜴和壁虎在进化上有很大差异，但我们发现这些进化枝在发育修饰上有相似之处，以产生它们的粘性趾垫。相对于祖先的足底鳞片发育，即鳞片脊沿指同步形成，有趾垫的壁虎和蜥蜴都表现出从远端到近端方向的攀瓣形成。两个进化枝都经历了发育重排，并且在其起源之后，趾垫形态的改变是通过相对较小的发育修饰发生的，这表明发育限制控制了蜥蜴粘性趾垫的多样化。
