FIG. 6.

Relationships between pleiotropic beneficial and antagonistic effects of two hypothetical genes. Gene A codes for the enzyme that makes metabolite M2, which can give rise spontaneously to a damaging product D. D can directly damage DNA, thus making Gene A antagonistically pleiotropic, and can induce the aggregation of the protein product of Gene B, thus making Gene B antagonistically pleiotropic. To see this illustration in color, the reader is referred to the web version of this article at www.liebertpub.com/ars