• Two kinds of variability in the Y chromosome have been assessed in relation to variability of human behavior. The first is the presence of a supernumerary Y chromosome, which is found in two karyotypic variants, 47,XYY and 48,xxyy. The second is inherited variability in the length of the Y chromosome, which results from variability in the length of the quinacrine-binding fluorescent segment. In this article, I review the evidence that these two kinds of variability in the Y chromosome are related to variability of human behavior, and I indicate the methodological and statistical difficulties that are encountered in assessments of such a relationship. My final purpose is to underscore the need for mapping of the Y chromosome and to elucidate the function of the constitutive heterochromatin that constitutes its fluorescent segment so that progress can be made in the study of the Y chromosome and the possible effect of its variability on behavior.
Dorus E. Variability in the Y Chromosome and Variability of Human Behavior. Arch Gen Psychiatry. 1980;37(5):587-594. doi:10.1001/archpsyc.1980.01780180101013