THE ETS MULTIGENE FAMILY IS CONSERVED THROUGHOUT THE METAZOA

This study provides the first empirical evidence for the conservation of the ets proto-oncogene transcription factor family throughout the M etazoa. Using the polymerase chain reaction with degenerate primers co rresponding to conserved sequences within the ETS DNA-binding domain, we have detected ets genes in a range of lower metazoans, including sp onges, ctenophores, anemones, flatworms and nematodes, and in several higher invertebrate metazoans. Many of these sequences are significant ly divergent from the original v-ets-1 oncogene, although most can be aligned with recently defined groups within the ets gene family. Multi ple ETS domain sequences were detected in a number of the lower metazo an species, providing evidence for the existence of an ets multigene f amily at the earliest stages of metazoan evolution. In contrast, we we re unable to detect any ETS sequences in fungal, plant or several prot ozoan DNAs. Our findings suggest that the duplication and divergence o f ets proto-oncogenes responsible for generating the multigene family occurred concomitantly with the development of metazoan animals. In ad dition, these data corroborate other recent molecular evidence in prov iding strong support for the monophyletic origin of all multicellular animals, including sponges.