Jan. 28, 2013 — Red coloration --
historically seen as costly in vertebrates -- might represent some
physiological benefit after all, according to research published in the
journal Physiological and Biochemical Zoology.
Pheomelanin, which is responsible for red hair and
freckles in humans and orange and chestnut coloration in other animals, is
known to increase the damage to skin cells and melanoma risk when present in
large amounts. Furthermore, its creation involves the consumption of
glutathione, a beneficial antioxidant.
In an attempt to unearth the factors favoring
the evolution of pheomelanin in spite of its costs, Ismael Galván and Anders P.
Møller of the University of Paris-Sud examined the survival from one breeding
season to the next of a wild European population of barn swallows, as well as
the annual survival rates of 58 species of American birds.
A recent hypothesis claims that the consumption
of cysteine (a component of glutathione) that occurs when pheomelanin is
produced can be beneficial under conditions of low stress. Cysteine, which is
mainly acquired through diet, can be toxic at high levels, so the production of
pheomelanin may help to sequester excess quantities of this amino acid.
No comments:
Post a Comment