Can you introduce photosynthesis gene in human?

Answer 1

Yes. Photosynthetic organelles, i.e. chloroplasts, could be introduced to human cells and theoretically work. although there are a number of limitations; firstly the structure of human skin cells currently would not allow for sunlight to reach the chloroplasts humans would need to develop a layer of clear cells such as the epidermal cells found on plant leaves. Secondly, even if somehow human skin cells developed or were engineered to have these traits this would mean to procure enough light energy we'd have to go au natural if you get my drift ;) and finally even if we did manage to incorporate chloroplasts and other photosynthetic mechanisms into our cells the likely-hood is that the energy produced by photosynthesis would have little benefit and we would still need to consume a large quantity of calories to survive. The only animals which incorporate photosynthesis successfully, such as the Elysia chlorotica, seem to be largely stationary and so do not have the energy requirement that a human would.

I guess the answer to your question is it can be done but there's not really much point to it :/