The Flaming Goldfish

As far as I can see, there is no way currently, because you'd have to transfer thoughts/memories to a new body. You also have to take into account that a different species with a different neurological structure would present a huge obstacle. Also, thoughts and memories are not stored as tangible "things" that you can transfer...at the basest level, they are simply electrochemical changes and impulses that we interpret as thoughts or memories. Even if we attempted to transfer through electrochemical bridges, how would we know what the body of the new species (the one we want to transfer to) is interpreting that as? Simply put, assume there are two bodies, A (a human) and B (a different species); even if we find a way to transfer the electrochemical impulses that constitute A's thoughts and memories from A to B, how can we be sure that B interprets/perceives them the same way A does? B could perceive a memory as garbled nonsense, or something entirely different.

Well, I'm not up to date on the literature or the specifics of it, but capsaicin is an irritant and can be a toxin, so I don't think our bodies have any natural uses for it. That isn't to say there are not medicinal uses; there probably are.

When you say genetic differentiation, are you referring to differentiation of cells or of populations? Within cells, DNA is responsible for coding protein sequences, and the types of proteins created have a huge influence on the function of the cell. When differentiation occurs in populations on the other hand, it is more influenced by evolutionary forces than strict genetics. The DNA of each organism confers certain traits or characteristics upon it. Organisms with characteristics that give them a beneficial advantage or allow them to adapt to their environment better will be better able to survive, and over the course of many years, will result in lots of accumulated differences between populations. Sometimes, these differences can result in (or be the beginnings of) speciation, where a population that is more isolated from the rest starts to diverge into a new species altogether.