Short, long, and beyond: Molecular and embryological approaches to insect segmentation

Over the past dozen years, studies comparing the expression of orthologues of the, Drosophila segmentation penes among various insects have served to broaden our view of the ways in which insects make segments. The molecular data suggest that, although the overall genetic mechanisms of segmentation during embryo-genesis have been conserved, the. details of this process vary both within and between various insect orders. Here we summarize comparative gene expression data relevant to segmentation with an emphasis on understanding the extent of molecular patterning prior to gastrulation. These results are discussed in embryological context with an eye toward understanding the evolution of segmentation within insects.