ABSTRACT
This introduction presents an overview of the key concepts discussed in the subsequent chapters of this book. The book attempts to compile the data on the frequencies of the abnormal hemoglobins, thalassemia, and the glucose-6-phosphate dehydrogenase deficiency in the world’s populations. The three major forces that can change the genetic characteristics of a population are: mutation, natural selection, and gene flow. Two other factors, random gene drift and the mating system of the population, can also influence the genetic characteristics or gene frequencies of a population. Gene flow migration and admixture, is the result of the exchange of individual organisms among populations. Random gene drift, which is simply the fluctuation in gene frequencies due to chance, is determined by the size of the population. The amount of gene drift that can occur varies inversely with the size of the population.
