How can you tell if a genetic mutation is positive or negative?
By survival. If the individual survives, and successfully competes in the competition for a mate, and therefore reproduces, then it is either positive or neutral. Many of the negative ones simply don’t survive at all, and the fetus is miscarried. Others create handicaps which would have been fatal in the brutal world of primitive man, but survive in the modern world due to compassion and family care. Nature is red in tooth and claw.
