Researchers at Stanford's Medical Center were spraying Arabidopsis plants (in the mustard family) with hormones to see if they could trigger any of the plants genes. They could, and the treated plants grew up stunted. But, it was serendipitously discovered, the same genes could also be triggered by spraying with water, by gusts of wind, and even by the human touch. Evident-ly, some of the genes in these plants can be turned on by various environmental stimuli, and thus affect future plant development. This mechanism per-haps explains why trees along the seacoast and timberline are stunted.
(Crawford, Mark H., ed.; "Nolo Me Tangere," Science, 247:1036, 1990.)
Comment. One is tempted to ask how widespread this phenomenon is in biology. Are humans, for example, born with a console of gene-buttons that the environment can push - as in cancer? Or, even in evolution itself?