Limb identity during development

Article By:

Naiche, L. A. Department of Genetics and Development, Columbia University, New York, New York.

Last reviewed:2008

DOI:https://doi.org/10.1036/1097-8542.YB081560

The vast majority of vertebrate species have two pairs of bilaterally symmetric limbs that emerge during early development. The anterior limbs form at the junction between neck and torso and are known as forelimbs, while the posterior limbs form at the junction of torso and tail and are known as hindlimbs. The forelimbs and hindlimbs each acquire different shapes during development. Depending on the species, forelimbs and hindlimbs will, respectively, form arms and legs (humans and other primates), wings and legs (birds), pectoral fins and pelvic fins (fish), or forelegs and hindlegs (most amphibians, reptiles, and mammals). Despite the dramatic difference between, say, a hawk's wings (forelimbs) and talons (hindlimbs), the early stages of forelimb and hindlimb development are virtually identical in appearance, which has led researchers to search for the factors that control the differences in the development of the limbs.

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