William Bateson, black slavery, eugenics and speciation: The relative roles of politics and science.

The peace of the world is challenged by societal confrontations that can often be labeled "racial" or "ethnic." Emblematic of this is discrimination based on skin colour. William Bateson's background suggests sympathy with the black emancipation movement. Yet the movement's success is attributed more to battles between political figures than between scientists with contending views on the biology of racial differences. However, in the long term, Bateson's contributions to slavery and eugenic issues may be seen as no less important than those of politicians. Mendel's discovery of what we now know as "genes" languished until seized upon by Bateson in 1900. For six exhausting years he struggled to win scientific acceptance of these biological character-determining units. Later, he pressed the Mendelian message home to the general public, opposing simplistic applications of Mendelian principles to human affairs, and arguing that minor genic differences that distinguished "races" - e.g. skin colour - do not initiate new species. Bateson praised the "physiological selection" speciation hypothesis of Darwin's young research associate, George Romanes. This enthusiasm was rekindled by Robert Lock and formulated in modern terms with C. R. Crowther. Thus, the spark that initiates a divergence into two species can be non-genic. This normal form of hybrid sterility, based on genome-wide DNA sequence differences, operates on, but has not succeeded in dividing, the human species. It should not be labeled "idiopathic," and be clearly distinguished both from pathological sterility and undiagnosed sterilities that may prove to be pathological. We are one reproductively isolated population, the human species.