Genetics studies the problem of heredity, namely why offspring resemble their parents. The field emerged in 1900 with the rediscovery of the 1865 work of Gregor Mendel. William Bateson called the new field ‘genetics’ in 1905, and W. Johannsen used the term ‘gene’ in 1909. By analysing data about patterns of inheritance of characters, such as yellow and green peas, Mendelian geneticists infer the number and type of hypothetical genes. The major components of the theory of the gene, which proposed the model of genes as beads on a string, were in place by the 1920s. In the 1930s, the field of population genetics emerged from the synthesis of results from Mendelian genetics with Darwinian natural selection. Population geneticists study the distribution of genes in the gene pool of a population and changes caused by selection and other factors. The 1940s and 1950s saw the development of molecular genetics, which investigates problems about gene reproduction, mutation and function at the molecular level.
Philosophical issues arise: the question about the evidence for the reality of hypothetical genes, and the status of Mendel’s laws, given that they are not universal generalizations. Debates have occurred about the nature of the relation between Mendelian and molecular genetics. Population genetics provides the perspective of the gene as the unit of selection in evolutionary theory. Molecular genetics and its accompanying technologies raise ethical issues about humans’ genetic information, such as the issue of privacy of information about one’s genome and the morality of changing a person’s genes. The nature–nurture debate involves the issue of genetic determinism, the extent to which genes control human traits and behaviour.
Exploring the Status of Population Genetics: The Role of Ecology
