Non-model systems in mammalian forelimb evo-devo

Abstract

Mammal forelimbs are highly diverse, ranging from the elongated wing of a bat to the stout limb of the mole. The mammal forelimb has been a long-standing system for the study of early developmental patterning, proportional variation, shape change, and the reduction of elements. However, most of this work has been performed in mice, which neglects the wide variation present across mammal forelimbs. This review emphasizes the critical role of non-model systems in limb evo-devo and highlights new emerging models and their potential. We discuss the role of gene networks in limb evolution, and touch on functional analyses that lay the groundwork for further developmental studies. Mammal limb evo-devo is a rich field, and here we aim to synthesize the findings of key recent works and the questions to which they lead.

Figure 1:. Diversity of Mammal Limb Development -

Schematic of limb development for sloths, mice, moles, ungulates, and bats through developmental time. Changes in developmental networks and expression patterns are indicated where known. Gray ovals in the hand plate and autopod represent early digit condensations. Orange ovals in the humerus represent secondary ossification centers. Bmp — Bone morphogenic protein; Fgf — Fibroblast growth factor; Shh — Sonic hedgehog. Expression patterns and networks from [56,17], respectively. Phylogeny based on [–69].