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Dark testicles strength protect birds from mutation, scientists find.

These findings could explain why such inky testicles are mysteriously institute throughout the birdlike kingdom.

Scientists convergent on the blueness melanin, which gives manlike skin its color. Curiously, researchers hit also seen melanin in the testes of a variety of species in every chordate groups. However, why this blueness is there and what it strength do was unknown.

Melanin is also an antioxidant that crapper protect the embody against reactive gas species, bruising compounds that crapper damage DNA. As such, scientists reasoned that melanin in testicles strength protect against transmitted mutations in sperm. [New Test Reveals Good vs. Bad Sperm]

Evolutionary scientist Ismael Galván at the University of Paris-Sud in author and his colleagues studied 134 species of birds, concentrating on modification rates in their mitochondria, which support cells respire gas and which possess their possess DNA. Sperm need a aggregation of oxygen, and some mutations in mitochondria could restrict gamete and thusly walk a bird's chances at reproduction.

The researchers institute the 42 species of birds with testicles darkened by melanin, such as owls and thrushes, had relatively higher modification rates in their mitochondria than the 92 other birds without inky testes. They also discovered that melanin was most ofttimes seen in testicles during the nurture seasons of birds, when gamete was likely generated. There was no link seen between scene of plumage and scene of testicles.

"Melanins are present in every organisms, from bacteria to mammals -- they are the most ordinary birdlike pigments," Galván told LiveScience. "These results suggest that the evolution of melanin-based traits haw be related to the genome."

"Our findings haw be well practical to other birdlike groups," Galván added. "Our study opens newborn and elating questions for future research."

If melanin does hit this conserving effect, digit discourse that comes to mind is why melanin is not institute in every testicles.

"We hypothesize that this is because of the costs of producing melanin, which haw stingy that the exclusive animals that melanize their testes are those that rattling need it because of their broad modification rates," Galván said.

The scientists careful their findings online Feb. 10 in the Journal of Evolutionary Biology.

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