Cell death genes in invertebrates and (maybe) vertebrates

That naturally occurring cell death in the nervous and other systems is an active and physiologically appropriate process has received much attention recently and has gained a significant degree of acceptance. The identification of cell death genes in invertebrates, the characterization of gene products that function as cell death suppressors, and the demonstration that some proto-oncogenes elicit cell death, as well as proliferation, in certain cell types have heightened interest in the mechanism of programmed cell death. Yet, evidence for a genetic program for cell death in vertebrates remains circumstantial and, so far, vertebrate 'cell death' genes exist only in theory.