advertisement
30 January 2013

Birds hold clues to why there are redheads

Red coloration—historically seen as costly in vertebrates—might represent some physiological benefit after all, according to research.

0

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.

What the research showed 

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.

Galván and Møller measured birds’ blood levels of uric acid and analyzed the coloration of their chestnut throat feathers (an indication of pheomelanin content). When they compared birds that had similar uric acid levels (and therefore similar capacities to excrete excess amino acids), they found that both the European barn swallows and the American birds with larger amounts of pheomelanin in their feathers survived better. 

This study is the first to propose that the costs/benefits of pheomelanin may depend on prevailing environmental conditions, and its results suggest that the production of this pigment may even be beneficial in some circumstances. Given that all higher vertebrates, including humans, present pheomelanin in skin, pelage, and plumage, Galván and Møller’s findings increase the scant current knowledge on the physiological consequences of pheomelanin and open new avenues for research that will help us understand the evolution of pigmentation.

(EurekAlert, January 2013)

(Photo of woman with red hair from Shutterstock)

Read more:

All about melanoma

 
advertisement

Get a quote

advertisement

Read Health24’s Comments Policy

Comment on this story
0 comments
Add your comment
Comment 0 characters remaining

Live healthier

Strenghten your immunity »

Keep your immunity strong Immune system boosters Boost your family's immunity

5 immune boosters in your kitchen

You don’t need a handful of vitamins and supplements to keep your body healthy, check out these five immune boosting foods you probably already have in your kitchen.

Laugh a little »

Eat yourself happy Laugh more and live longer Laughing yoga the best medicine

The healing power of laughter

A good chuckle doesn't only make you feel happy for a moment, it's beneficial to your health too.