Lamarckism
n. the theory that changes acquired by an organism during its lifetime—for example, through use, disuse, or injury of particular parts—can be inherited by its offspring. Extensive research over centuries failed to find proof of such inheritance of acquired characteristics; however, evidence now suggests that epigenetic modifications (i.e., natural or environmentally induced changes to DNA expression that occur during an organism’s lifetime) can result in acquired characteristics that may be inherited by offspring. Also called use-and-disuse theory. [Jean-Baptiste Lamarck (1744–1829), French natural historian]
—Lamarckian
adj.