New Tools for an Old Problem

Abstract

Human behavior is the most complex and difficult problem ever attacked by geneticists, and it is likely to resist their best efforts for a full explanation for many years to come. In fact, it is quite likely that classical genetics would never be able to solve the most puzzling problems in behavioral genetics. This difficulty in understanding human behavior arises for several reasons. The first major problem for the behavioral geneticist is that human behavior is far more complicated than the simple physical traits that Mendel was able to study in his pea plants. When Mendel did his breeding experiments he could look at a pea seed and easily determine whether that seed was smooth or wrinkly, but human behavioral options cannot be so easily dichotomized. The second major problem is that, unlike most of the research for which classical genetics is best suited, human behavior does not involve one or a few genes. Instead, human behavior is determined by a large number of genes, each of which probably has a small effect, and there may even be many different combinations of genes that result in the same behavior.