THE HOMEOTIC GENE LIN-39 AND THE EVOLUTION OF NEMATODE EPIDERMAL-CELLFATES

The fate of ventral epidermal cells differs among nematode species. No nvulval cells fuse with the epidermis in Caenorhabditis elegans, where as the homologous cells undergo apoptosis in Pristionchus pacificus. T he homeotic gene lin-39 is involved in the regulation of these epiderm al cell fates. in Caenorhabditis, lin-39 prevents cell fusion of poten tial vulval cells and specifies the vulva equivalence group. Pristionc hus vulvaless mutants that displayed apoptosis of the vulval precursor cells were isolated, and point mutations in lin-39 were identified. T hus, the evolution of these epidermal cell fates is driven by differen t intrinsic properties of homologous cells.