The main advantage of genetic variation is that it increases the chance of survival of the organisms. The nature always selects the fittest organism. So if there was no variation in genetic make up of the organisms, there would not have been so many species of the organisms living in this world. For instance, Dinosaurs were a type of lizards. They belonged to class Reptilia. All the lizards are thought to have a common ancestor. But then the genetic variations made the next generations of that ancestor different to each other. Dinosaurs did not have a great genetic make up, which the other lizards had. The other lizards fought for their existence because they were saner than the dinosaurs. Their variation from dinosaurs enabled them to do that. So the nature selected the fittest ones and let the dinosaurs to get extinct.