Robert Skipper has an enormous post on R.A. Fisher & Sewall Wright's theories of dominance. I think Wright was more in the right on this issue, remember, it is easier to break (lose function) than make (gain function).
More like this
David's penultimate post on Sewall Wright, Notes on Sewall Wright: The Shifting Balance Theory - Part 1:
Notes on Sewall Wright: the Adaptive Landscape:
David takes a slight detour in this Sewall Wright, series, R.
Notes on Sewall Wright: The Shifting Balance Theory (Part 2):