Phenotypic plasticity can potentiate rapid evolutionary change.
Using a computational model of string-like haploid genotypes, we verify the conjecture (J. Theor. Biol. 188 (1997) 153) that phenotypic plasticity can speed up evolution. The corresponding real-life situation was realized by Waddington in experiments carried out on the fruit fly Drosophila. Waddington found that after selecting for an environmentally induced trait over a number of generations, a new, true-breeding phenotype resulted that was absent in the starting population. The phenomenon, termed 'genetic assimilation', continues to attract interest because of the rapidity of the effect and because of its seemingly Lamarckian implications. By making use of a genetic algorithm-based approach developed previously, we show that conventional Darwinian selection acting on regulatory genes can account for genetic assimilation. The essential assumption in our model is that a structural gene can be in either of three allelic states. These correspond to its being (a) 'on' or 'off' constitutively or (b) in a plastic state in which the probability that it is 'on' or 'off' is influenced by regulatory loci in a dosage-dependent manner.
Behera
Narayan
N
Jawaharlal Nehru Centre for Advanced Scientific Research, Jakkur, Bangalore 560004, India.
Nanjundiah
Vidyanand
V
D000818:Animals; D005075:Biological Evolution; D019295:Computational Biology; D014644:Genetic Variation; D008954:Models, Biological; D010641:Phenotype; D012641:Selection, Genetic