Which of the answer choices are reasons why a population on an island might have less genetic diversity throughout the genome than a population on a nearby mainland? Select all that apply. Habitats on the island are the same as the mainland, so natural selection would favor the same alleles. Alleles may have been lost through random chance because not all individuals were able to mate. Island populations are more likely to have non-random mating than mainland populations. The original colonizers of the island do not contain all of the genetic diversity of the larger mainland population.