For one particular autosomal gene, a population of 400 people contains 800 alleles, two each. Not enough information has been given to know how much genetic diversity is present in this population at that locus. If all 800 alleles are identical, each person is homozygous at that locus. Perhaps one person carries a new unique mutation. Perhaps several different mutations are present in this population, inherited. The population will be in Hardy Weinberg equilibrium for the distribution of these variant alleles if the assumptions are met, that is, if mating is random relative to the alleles of that gene. However, if a mutation confers a selective advantage or disadvantage, with mating being selective rather than random, then the population will not be in Hardy-Weinberg equilibrium.
