Population genetics is the scientific field that examines the distribution and dynamics of genetic variation within and among biological populations. It quantifies allele and genotype frequencies and investigates the evolutionary forces—such as mutation, gene flow, genetic drift, and natural selection—that influence their changes over generations using mathematical models and statistical analyses. This discipline provides the theoretical and analytical framework for understanding evolutionary processes, population structure, and the genetic basis of adaptation and has fundamental significance across biology, including conservation, agriculture, and medicine.