I've been doing some "google-research" and found some things (not in peafowl, just searching for "progressive pied" or "mottle pied"). I found:
http://www.agapornis.be/artikels/dosmottle1.html
http://www.agapornis.be/artikels/dosbont1.html
On another page (rather tedious even for geeky ME to read), I saw discussion of "progressive pied" resulting from a sort of immune reaction, causing random and progressive destruction of melanocytes (the cells that make pigment), likening it to vitiligo seen in humans.
The "progressive pied" phenotype varies across species with respect to inheritance -- in some species, there is a simple one-gene recessive inheritance, while in others, multiple genes are presumed to be in effect based on experimental breeding outcomes, but the genes have not been identified.
So, in other words, after trying to learn more, I've learned I know even less.
hehe
Still a beautiful bird, though....and that's what counts.

~Christopher
http://www.agapornis.be/artikels/dosmottle1.html
http://www.agapornis.be/artikels/dosbont1.html
On another page (rather tedious even for geeky ME to read), I saw discussion of "progressive pied" resulting from a sort of immune reaction, causing random and progressive destruction of melanocytes (the cells that make pigment), likening it to vitiligo seen in humans.
The "progressive pied" phenotype varies across species with respect to inheritance -- in some species, there is a simple one-gene recessive inheritance, while in others, multiple genes are presumed to be in effect based on experimental breeding outcomes, but the genes have not been identified.
So, in other words, after trying to learn more, I've learned I know even less.
hehe
Still a beautiful bird, though....and that's what counts.

~Christopher