?Our load of mutations? revisited

Abstract

"The original source of my interest in genetics had been my long harbored idea of the control of evolution of man by man himself."' Thus declared H. J. Muller in an autobiographical sketch prepared, at Nikolai Vavilov's request, in 1936-1937. According to these notes, Muller's eugenic interests ofiginated with a visit, at the age of about eight, to the American Museum of Natural History. Through the example of the succession of fossil horses' feet, Muller's father convinced him of the theory of natural selection. "And from that time," he wrote, "the idea never left the back of my head that if this could happen in nature, men should eventually be able to control the process, even in themselves, so as greatly to improve upon their own natures." 2 It would be naive to take Muller's account at face value. But whether or not his eugenic enthusiasms actually dated from childhood, or prompted his interest in genetics, they were certainly evident by his student days and informed much of his scientific work.3 Eugenics, as Elof Carlson has noted, was "the leitmotif of Muller's life."4 His first paper, written at the age of nineteen, developed a eugenic argument 5and so did his last, written at the age of seventy-six.6 Muller's final project, in collab-