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Traits produced by melanin may signal the bearer's capacity to combat free radicals
October 06, 2008Some animal species have developed conspicuous traits produced by melanin pigments (for instance, dark manes in lions, black stripes in some birds and fishes). These traits are used as signals during contests for resources and/or contribute to increase the mating opportunities. However, the efficiency of these traits as signals depends on the fact that they transmit honest information about the quality of the bearer. This would be only assured by the fact that producing or maintaining the signal inevitability implies a cost. Thus, only those individuals able to afford the cost would also be able to conveniently express the signal.
Signals produced by melanin pigments have challenged our understanding because they are apparently cost-free and strongly controlled by the genotype. Melanin pigments are not as limited in production as carotenoids, yellow-red pigments common in vertebrates and only obtained from certain food items. In fact, melanin is constructed from amino acids present in proteins of the organism. However, recent experimental studies have become to disentangle the cost at the basis of melanin-based signals.
A recent article by Ismael Galván at the Museo Nacional de Ciencias Naturales (CSIC) in Madrid and Carlos Alonso-Alvarez at IREC-CSIC, Spain, published in the online, open-access journal PLoS ONE proposes a novel hypothesis suggesting that these traits could indicate the ability of the bearer in fighting free radicals and oxidative damage. On the basis of medical bibliography, the researchers realized that tissue melanization is constrained in the presence of high enough levels of a key intracellular antioxidant named glutathione, which is considered one of the most powerful antioxidants present in virtually all animal cells.
The scientists hypothesized that low levels of this substance are also required to express melanin-based signals present in many animals. This implies that individuals able to express these signals should be also able to fight off an oxidative challenge, as a consequence of the low levels of the cited antioxidant. Only those animals with alternative antioxidant resources would be able to afford the cost of signaling. By chemically inhibiting the production of glutathione at the red blood cells, authors were able to significantly increase the size of a black stripe present in the feathers of the breast of great tits (a common garden bird). This stripe is a conspicuous trait playing a significant role during combats for territory, food or mates.
Furthermore, the reduction of glutathione levels also induced a mobilization of other antioxidant molecules to the blood plasma, supporting the cost, such as hypothesized by Alonso-Alvarez and colleagues.
Public Library of Science
The scientists hypothesized that low levels of this substance are also required to express melanin-based signals present in many animals. This implies that individuals able to express these signals should be also able to fight off an oxidative challenge, as a consequence of the low levels of the cited antioxidant. Only those animals with alternative antioxidant resources would be able to afford the cost of signaling. By chemically inhibiting the production of glutathione at the red blood cells, authors were able to significantly increase the size of a black stripe present in the feathers of the breast of great tits (a common garden bird). This stripe is a conspicuous trait playing a significant role during combats for territory, food or mates.
Furthermore, the reduction of glutathione levels also induced a mobilization of other antioxidant molecules to the blood plasma, supporting the cost, such as hypothesized by Alonso-Alvarez and colleagues.
Public Library of Science
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Melanin: The Chemical Key To Black Greatness (Black Greatness Series) by Carol Barnes (Author) This book, is designed to familiarize the Black Human with Melanin and its importance to life, memory processes, ancient African history, sunlight, music, dancing, anti-aging, anti-cancer, religion, electromagnetism, and any other scientific and cultural parameters. |
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Source Naturals N-Acetyl L-Tyrosine 300mg, 120 tablets by Source Naturals Dietary supplement. N-Acetyl L-Tyrosine is a more rapidly absorbed and bioavailable form of the amino acid L-tyrosine, and is less prone to urinary excretion. L-Tyrosine is converted in the body to key biologic compounds, including epinephrine, dopamine, L-dopa, CoQ10, thyroid hormones, and melanin. The B vitamins pyridoxine (B-6) and folic acid are provided to assist in the conversion process (These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease). Suitable for vegetarians. Contains no yeast, dairy, egg, gluten, soy or wheat. Contains no sugar, starch, preservatives, or artificial color, flavor or fragrance. |
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Why Darkness Matters : The Power of Melanin In the Brain by Ann Brown (Author) Asking the question, Are people with dark skin truly different?, these essays consider the history, science, and psychology of melanin. With contributions from such noted writers and scholars as Hunter Adams, Ann Brown, Richard King, and Owen Moore, these writings explore the history of people with surface skin melanin. The genetic influence of melanin on culture and learning is also addressed, with a specific look at the unfair treatment of African American children in schools that has led to poor IQ test scores and disproportionate numbers of African American children in special education classes. |
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Meladine All Natural Melanin Enhancer (4 oz) by Meladine Today thousands of women are annoyed and embarrassed by tiny blonde hairs, frequently referred to as "peach fuzz", that often cover the sides of the face, the abdomen and other areas of the body. And even though we are now able to walk on the moon and clone a sheep, until recently, there has been no permanent solution for this pesky problem. Today, many women still resort to repeated waxing treatments, tweezing and even shaving. And for those who have considered resolving the problem through laser hair removal, the fact is that 30% of those seeking this procedure cannot be treated due to a lack of pigmentation in the hair. Meladine is a natural melanin enhancer solution which, when sprayed on the desired area, selectively deposits natural melanin directly into the hair... |
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2008 Face & Legs Hard to Tan Places w/ Melanin Booster & Light DHA 8 Oz by Norvell/Body Invest 2008 Face & Legs Hard to Tan Places w/ Melanin Booster & light DHA 8oz Face-Leg Tanner/Melanin Booster Specialty tanning lotion for hard to tan places with melanin booster. Hypo allergenic and non-sensitizing. Blended with the highest active levels of fine raw materials to tan delicate and hard to tan places. Wonderful fresh peach honey fragrance. |
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The Science of Melanin: Dispelling the Myths by T. Owens Moore (Author) In this ground-breaking work, perhaps the first full length scientific analysis of the substance found in practically all living organisms and inanimate objects, T. Owens Moore attempts to dispel the myths and rectify the common misconceptions associated with melanin. In part one, he focuses on writers of five key texts that employ an African-centered perspective. The recurring theme espoused by these writers is that melanin alone is the entity that makes black people psychologically and behaviorally different from non-black people. Nothing could be farther from the truth, argues Moore. |
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UVEX MP-VII Melanin Polarized Sunglasses (Matte Black) by Uvex Featuring Melanin. With over 500 million years of development by nature, it provides a powerful defense against sunlight damage. A patented process now creates Melanin that is formulated into the matrix of high performance polycarbonate sunglass lenses, creating the ultimate in sun protection. The lenses in the MP series are also Polarized, adding additional protection against reflected glare (especially useful on or near snow or water). |
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