That a trait is preferable and not developed can never be an indicator of what a gene is for. The fact that I didn't evolve to fly doesn't mean I don't have the

That a trait is preferable and not developed can never be an indicator of what a gene is for. The fact that I didn't evolve to fly doesn't mean I don't have the potential genes for that. There's also far less natural selection in evolution than we think. Evolution overwhelmingly happens in relatively short time periods, after which stability seems to take over. This is at odds with the natural selection principle as the primary driver of evolution. Also, most DNA-sharing between organisms happens horizontally, not top down (think single cell organisms). There's really much more that we don't know than what we know here.