It is known that radiotrophic fungi use melanin to make use of gamma radiation. It is also known that melanin protects human skin from UV radiation.

Thus I wonder whether melanin protects humans from gamma radiation as well?

Are the black people and tanned white people less vulnerable to gamma radiation?


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    $\begingroup$ Please provide a reference for the claim in the first sentence. Also just because a simple organism may have developed a novel use for a compound doesn't mean that can be extended to humans. And as gamma radiation penetrates deeper than UV, its effects go beyond the layer of skin that melatonin serves to protect. $\endgroup$ – AMR Sep 30 '15 at 3:09
  • $\begingroup$ gtcceis.anl.gov/guide/rad/index.cfm $\endgroup$ – AMR Sep 30 '15 at 3:16
  • $\begingroup$ @AMR the fungi use gamma-ray energy as energy source for growth. The growth in fungi is not because of mutations but because it is such a biological mechanism to utilize energy from environment. $\endgroup$ – Anixx Oct 1 '15 at 1:51
  • $\begingroup$ You do not want human cells to get a growth advantage, and no it is not even remotely protective against gamma rays to have extra melanin. You cannot compare the adaptations of a single celled organism to the processes of a complex multicellular organism in that respect. $\endgroup$ – AMR Oct 1 '15 at 1:53
  • $\begingroup$ @AMR it protects from UV, any hint that it would not work against gamma? $\endgroup$ – Anixx Oct 1 '15 at 1:55

Since it is clear from the source in your question that melanin can absorb energy from gamma rays, yes higher concentrations of it would reduce the energy of gamma rays getting through the skin. However this would not provide any real relative protection, the gamma rays are still going to go right through your skin and start damaging DNA.

Gamma rays are three orders of magnitude higher frequency and therefore carry much more energy than UV. Of course there are energy transfer inefficiencies but since the fungus are not growing at even an order of magnitude faster, it's fair to say that melanin is not absorbing all of the energy in a gamma ray.

Since the gamma rays are not fully absorbed by melanin, they will still go through the skin and will still be able to do significant DNA damage.

So yes, but not enough to really matter.

Frequency Differences


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