Goals of Population Genetics 1. To describe how the frequency of an allele Which controls a trait changes over time 2. To analyze the factors that lead to changes in gene(allele) frequencies 3. To determine how changes in gene(allele) frequencies affect evolution and speciationGoals of Population Genetics 1. To describe how the frequency of an allele which controls a trait changes over time； 2. To analyze the factors that lead to changes in gene (allele) frequencies； 3. To determine how changes in gene (allele) frequencies affect evolution and speciation