Many aquatic invertebrates possess complex life cycles, which include
a switch from a vegetative to a sexual mode of reproduction. While sex
ual reproduction is usually linked to slow rates of propagation, veget
ative reproduction leads to high rates of clonal propagation and a fas
t increase in population size. I have attempted to identify developmen
tal genes which are differentially expressed between sexually and vege
tatively reproducing individuals. Quantitative assays of the expressio
n of those diagnostic genes could be applied to field samples to gain
information on the reproductive status of the sample. Here I outline a
general strategy for identifying and testing the usefulness of homeob
ox genes as candidates for regulatory genes whose expression patterns
are indicative of a sexual or vegetative developmental phase.