Comparison of gastrulation in frogs and fish

Abstract

SYNOPSIS. Comparative embryological studies of frogs and fish provide valuable information about the mechanisms and evolution of vertebrate development. First, by mapping developmental data from a range of species onto a cladogram, one can distinguish general features of a ground plan from variation within it. Two studies illustrate this: comparison of gastrulation mechanisms in sturgeon and Xenopus, and morphogenesis of the dorsal mesoderm in five species of anurans. Second, phylogenetic analysis of developmental data makes it possible to identify radical departures from the ground plan among related groups. Teleost gastrulation is a highly derived process that appears to have little in common with the ancestral version. However, teleost gastrulation may have evolved as a result of two specific developmental changes: loss of bottle cells in the surface layer, and changes in the yolk. The phylogenetic distribution of developmental characters forms the basis for mechanistic hypotheses about the origins of major evolutionary changes in development ©1994 by the American Society of Zoologists.