I think DNA in plants transits light via photosynthesis, We humans though made of atoms , cells, which contain our genetic imprint does not use light. What about those people who live in countries where there is six months of darkness and light. There genetic make up is essentially the same. It's codes do not differ. Unless there are genetic illnesses that occur in them which does not occur in people that live in the US A-G-T-C-U I'd look up rare genetic mutations in say Greenland.