Date of Award

Spring 1950

Document Type



Life & Environmental Sciences


As geneticists look back, they see that mutated genes must have been responsible for innumerable new characteristics in all kinds of animals and plants within the last few hundred years. From the Massachusetts farmer who found a peculiar lamb with a long, sagging back and very short legs that made It impossible for him to jump fences, to the hornless Hereford calf that appeared in a Kansas herd, have stimulated many as to the cause of these mutations.

Darwin was aware that new characteristics inexplicably cropped out in living things, but not knowing anything about genes, he could not attach any importance to them. Today, the entire concept of evolution centers around gene mutation.

Gene mutations happen so rarely under natural conditions that geneticists have had little opportunity to find what causes them. Even among the carefully watched Drosophila, thousands of flies had to be counted and watched for every mutation that was found. The cause of these natural mutations are unknown, but natural and artificially caused mutations are brought about, and it is in this realm that we shall investigate.