“These are all black and white, I want something different!”
Selection for tameness leads to changes in hormone chemistry, physiology, and development. These changes have wide-ranging effects, including changes in coat color. In particular, calmness and docility are associated with black coat color (Keeler 1942) and patches of white fur (Trut 1997). The process of domestication may therefore have increased the incidence of black and hooded rats in the domestic rat population.
How the hooded gene may influence behavior?
Pigment cells aren’t just found in the skin and hair follicles. They are also found in the central nervous system, including areas of the brain related to mood and response to stress.
Therefore, by selecting for docility in rats, humans select for changes in the biological systems that underlie behavior — the hormonal and neurochemical systems. Changes in these systems have far-reaching effects.
In the case of the hooded mutation, selection for docility led to a change in developmental timing: a delay in migration of pigment cells. This delay changed the neural profile of the brain in areas related to mood and stress, and, incidentally, this delay caused a piebald (hooded) coat. (http://www.ratbehavior.org/)
How the hooded gene may influence behavior?
Pigment cells aren’t just found in the skin and hair follicles. They are also found in the central nervous system, including areas of the brain related to mood and response to stress.
Therefore, by selecting for docility in rats, humans select for changes in the biological systems that underlie behavior — the hormonal and neurochemical systems. Changes in these systems have far-reaching effects.
In the case of the hooded mutation, selection for docility led to a change in developmental timing: a delay in migration of pigment cells. This delay changed the neural profile of the brain in areas related to mood and stress, and, incidentally, this delay caused a piebald (hooded) coat. (http://www.ratbehavior.org/)