NEO-DARWINIAN DEVELOPMENTAL EVOLUTION - CAN WE BRIDGE THE GAP BETWEENPATTERN AND PROCESS

In the past decade, there has been a surge of renewed interest in the study of developmental evolution. One approach that has been taken is to examine the expression patterns of a candidate gene in divergent ta xa and to use these results to infer which aspects of a particular gen etic pathway are either conserved or altered, Here we consider this ap proach from the perspective of the neo-Darwinian paradigm for evolutio nary change. If adaptations are typically composed of large numbers of gene substitutions that are of small effect individually, then the ca ndidate gene approach is unlikely to bridge the gap between developmen tal pattern and evolutionary process: changes in gene expression patte rns may identify the steps in developmental pathways that have been al tered during evolution but fail to identify the actual genetic changes that have occurred. On the other hand, there is growing support for t he view that adaptations often involve large-effect genes; fortunately , the candidate gene approach is well suited to this type of genetic a rchitecture.