Trojan Genes and Transparent Genomes: Sexual Selection, Regulatory Evolution and the Real Hopeful Monsters

Potential impacts of genetically modified (GM) animals in natural environments are explored in a framework of regulatory evolution. Transgenic growth hormone animals express remarkable alterations and plasticity in development, physiology and behavior in response to environmental factors (nutrition, temperature, photoperiod), suggesting that standard laboratory assessments are likely to underestimate their evolutionary potential. Sexual selection is examined in the context of female self-referent appraisal of male fitness that reflects performance in the species-specific niche. Wild-type females may recognize and discriminate against GM males (the Transparent Genome Hypothesis) but if accepted as mates, pleiotropic disruption associated with GMs may reduce fitness of the natural population (the Trojan Gene Hypothesis). Alternatively, facilitation of regulatory evolution by sexual reproduction (recombination and segregation) may derive modifier selection, masking, integration, or niche shifts. Other aspects explored include mutation theory, purging, pleiotropy, epigenetics and plasticity, behavior and the Bruce effect, and mismatch of genetic or epigenetic background between GM stock and natural populations.