There is significant evidence to suggest that at least some complex features of organisms result from what biologists call exadaptation, a phenomenon in which one genetic mutation confers a certain kind of survival advantage on an organism, and later, after subsequent mutations have occurred, the original mutation combines with the subsequent ones to confer a wholly different advantage. (firstthings.com)
But in a smaller population with fewer individuals reproducing, the original mutation can be preserved and continue to do damage. (sciencemag.org)
«We need to better understand how other genes may interact with the original mutation to cause cancer in the child,» Maris said. (sciencedaily.com)