Polygenic mutation in Drosophila melanogaster: estimates from response to selection of inbred strains

An average divergence, following 125 generations of selection of 12.0 abdominal and 8.2 sternopleural bristles from the accumulation of new mutations influencing bristle number, resulted from replicated divergent artificial selection for abdominal and sternopleural responses from an inbred strain of Drosophila melanogaster. Extremely asymmetrical responses to selection were evident. Low abdominal and high sternopleural bristle numbers exhibited greater numbers.