George H.F. Nuttall (1904:4) wrote: “The persistence of the chemical blood-relationship between the various groups of animals serves to carry us back into geological times, and I believe we have but begun the work along these lines, and that it will lead to valuable results in the study of various problems of evolution.” While enormous strides have been made in the field of molecular genetics, Nuttall's statement is still true. Our knowledge of the systematics of Old World monkeys, gleaned from both morphological and molecular approaches, is still poorer than many would admit.
In the 1960s, Nuttall's immunological approach was enhanced and used extensively by anthropologists and biochemists studying primates (Goodman, 1961, 1963; Sarich and Wilson, 1966, 1967). Karyological research by, for example, Chiarelli (1966) and Dutrillaux (1979) has also played a major role in primate evolutionary studies. The recognition of the potential of a “molecular clock” by Zuckerkandl and Pauling (1962) led to studies of protein sequences (Goodman et al., 1987). Research on primate DNA itself, and not merely its products, began in the late 1960s and early 1970s (Kohne et al., 1972; Benveniste et al., 1976), and was followed by restriction enzyme analyses of relationships among and between primate species and populations (Templeton, 1983; Melnick et al., 1993). The mapping and sequencing of portions of primate mitochondrial and nuclear genomes has also contributed greatly to primate systematics and population genetics (reviewed in Honeycutt and Wheeler, 1989; Koop et al., 1989; Melnick and Hoelzer, 1993).