“…The genetic architecture of discrete traits has been assessed through studies performed on mice (Grü neberg, 1952;Deol et al, 1957;Leamy, 1974;Self and Leamy, 1978;Richtsmeier and McGrath, 1986) and rhesus macaques (Cheverud and Buikstra, 1981;McGrath et al, 1984) and through pedigree studies on humans (Torgersen, 1951;Grü neberg, 1963;Berry, 1968;Lane, 1977Lane, , 1978Sjøvold, 1977Sjøvold, , 1984Saunders and Popovich, 1978;Heinrich and Teschler-Nicola, 1991;Velemínský and Dobisíková, 2005;Carson, 2006). Consequently, there is a large literature discussing the heritability of nonmetric traits and their utility for representing genetic variation [see, for review, Stefan and Chapman (2003), Hanihara and Ishida (2001a-d), and Carson (2006)].…”