an elementary, distinct genetic trait that is distinguishable in the phenotype of a given individual. The term was introduced in 1909 by the Danish geneticist W. Johannsen. Beginning in the 1960’s, it has been used in studies on population zoology and population botany to designate characters (markers) of the genotypic composition of populations, an approach permitting a genetic analysis of those species whose genetic investigation would otherwise be difficult or impossible. The isolation and classification of phenes is a major trend of research in genetics and population biology. The study of the distribution of phenes within populations and species is the task of phenogeography.