Have you ever heard of a guy named Charles Darwin?In a natural world there is very little chance of inbreeding.
Or the very basics understanding of variation within a species. Know the difference between eastern elk, Rocky Mountain elk,Tule elk, Manitoban elk, marrium elk and Roosevelt elk?
How about the difference between the Florida panther and the mountain lion?
Black tailed deer and mule deer?
The list could go on and on.
They are all variations (subspecies ) of the same species. That are genetically different from others in the species due to isolation and genetic inbreeding.
one of the key components in evolution is those genes that are of beneficial for survival in a area will be passed on to the next generation and those specific genes will become more prevalent in a particular population. If that isn't inbreeding I don't know what is .