Genetic diversity within a population arises through two main mechanisms. What are they?

1. Genetic diversity in a population comes from two main mechanisms. 2. The first is mutation, a change in DNA that is the ultimate source of new alleles. 3. The second is sexual reproduction, which assembles unique combinations of alleles in each offspring. 4. Geographic isolation and gene flow are discussed elsewhere as factors in speciation, not as the two main sources of genetic diversity within a population. 5. Natural selection acts on existing variation rather than generating new genetic variation itself, so it does not belong in this pair. _Source: OpenStax Biology (1st ed., CC BY 4.0), Ch 18 "Evolution and the Origin of Species", section Processes and Patterns of Evolution_