Integration or disintegration?

The first dilemma faced by a student of science is the choice of the problem and of the method of its investigation. He or she can be interested in general or specific questions, and it is not unreasonable to suppose that the final decision may be influenced, at least indirectly, by his/her genetic constitution. Even a superficial perusal of the present biologic literature reveals that the emphasis is now on a reductionist approach to the problems, and not on more synthetic evaluations.

As was emphasized by Mayr (1982), the term ‘reduction’ has been used with at least three different meanings, which he classified as constitutive, explanatory, or theory reductionism. A systems approach to biology, however, suggests that its phenomena have the peculiarity (termed by many as emergence) that the characteristics of the whole cannot be deduced from the simple knowledge of its components.

This idea is especially important when we are considering problems of human evolution, since it is difficult to dismiss any aspect of our biology or environment as not being important. This interdisciplinary approach was asserted as most important, for instance, by two groups of specialists assembled by the World Health Organization some years ago (WHO, 1964, 1968).

Attempts to evaluate the genetics and evolution of human populations at the continental or world level are scarce. The most recent, encyclopedic effort, was that of Cavalli-Sforza et al. (1994), in which they covered all continents in a systematic way, establishing afterwards main generalizations. In their treatment of the Americas, however, they restricted their attention to Amerindians only.