Directly altering DNA is merely the coarsest means to alter genetic expression. Epigenetics takes genetic engineering to a whole new level of subtlety.
Evolution can occur through the epigenetic dimension of heredity even if nothing is happening in the genetic dimension. ~ Israeli geneticist Eva Jablonka & English evolutionary biologist Marion Lamb
The DNA double-helix presents a malleable script. A wide variety of regulatory actions may adjust gene expression. Life experiences are encoded epigenetically and may be passed on to cell offspring, affecting an organism and its progeny without shifting DNA sequences.