Question

From the perspective of adaptation, does it matter if traits under selection arise in another species versus already occurring as standing genetic variation or as a new mutation within a lineage? What implications does this have for the origins of genetic novelty in a species by genetic modification (e.g., GMOs)?

Answer 1

In natural populations, organisms evolve new adaptations with respect to changing environments. These adaptations could be an outcome of already existing genetic variation in a population or by accumulating new mutations. In natural conditions, the genetic variation (be it existing or evolved) in the given population directly affects its fitness. Genetic variation in another species does not directly affect the fitness of a given species.

For example, if two different species are inhabiting a common habitat and both of them can be infected by a pathogen. If one species develop resistance to infection, the incidence of infection in another species is increased as the number of total potential susceptible hosts is reduced. It is an indirect negative effect. In other cases, the effect can be positive as well.

However, it can have direct consequences in artificial conditions. In the same above example, we can isolate the resistance gene from one organism and insert it into another species so that both species are now resistant to the pathogen.