MtDNA haplogroup I may improve light absorbtion and sleep & cut risk of schizophrenia

MtDNA haplogroup I may improve light absorbtion and sleep & cut risk of schizophrenia

I have noticed that haplogroup I (mtDNA) is defined by a rare mutation (T10034C) in tRNA encoding Glycine. This amino acid is a known an inhibitory neurotransmitter in the central nervous system, especially in the spinal cord, brainstem, and retina. Variations in the production of glycine in the mitochondria could affect the quality of sleep and the risk of schizophrenia (both positively if production is increased).

Glycine also happens to be a biochemical precursor of porphyrins, organic compounds that strongly absorb light, which is then converted to energy and heat in the illuminated areas. Porphyrins have been used in the context of photodynamic therapy and macular degeneration.

My hypothesis is that carriers of the T10034C mutation (i.e. all members of haplogroup I) absorb light more efficiently due to an increased production of glycine and porphyrin. That would explain why haplogroup I, which apparently came to Europe with Near Eastern Neolithic farmers as N1a and developed very late (not found in any Neolithic sample so far, which are all N1a to N1a1a), seems to have undergone a positive selection in northern Europe, where light is more scarce. Haplogroup I is especially common around the Baltic, in north-west Russia and in the cloudy British Isles.

In contrast haplogroup I is completely absent from the Maghreb and places like Syria, where excessive light would have caused its carriers to develop porphyria or macular degeneration.

If confirmed this could have important implications for people of (northern) European descent living in regions with strong sunlight like the southwest of the USA, Australia, or even Spain (where lots of Britons have moved).

Good research, thanks.

I cannot immediately see anything unreasonable about this theory, as a matter of fact, I think it is very plausible.
I think you may be onto something here.

Glycine, as we know, can indeed play a stimulatory and a depressant role in the brain.
[ Glycine supplements are often promoted to help quality of sleep.]
Sleep itself has been linked as one potential cause for, rather than symptom of, schizophrenia.
That those of said haplogroup might need undergo adaptation to absorb light, is quite logical. That it appears in the right places it would need to do so, adds weight to the theory.
I think it would be very interesting to see this theory put to the test.

hope said:

I cannot immediately see anything unreasonable about this theory, as a matter of fact, I think it is very plausible.
I think you may be onto something here.

Glycine, as we know, can indeed play a stimulatory and a depressant role in the brain.
[ Glycine supplements are often promoted to help quality of sleep.]
Sleep itself has been linked as one potential cause for, rather than symptom of, schizophrenia.
That those of haplogroup I might need undergo adaptation to absorb light, is quite logical. That it appears in the right places it would need to do this in, adds weight to the theory.
I think it would be very interesting to see this theory put to the test.

Click to expand...

Actually, I (mtDNA) mutation (T10034C), passed the test in real environment. It is a prime example (if indeed confirmed, as you said), how evolution works. As Maciamo mentioned, this mutation arrived from Middle East, but it really "bloomed" around Baltic Sea, place with weaker sun and overcast sky. This mutation popped up spontaneously in Middle East, in sort of benign form, not much helpful if any, but also not much destructive, letting people to survive just fine. However, when it moved to the right geographical area, it gave its carriers a powerful boost in survival.