M A T H E R ( 1941 ) hypothesized that there are two levels of genotypic organization, a genic balance within a single chromosome (internal balance), and a genic balance which exists between homologous chromosomes (relational balance). He demonstrated the existence of internal balance, and inferred the existence of relational balance from the predominance of heterozygotes found in wild populations. He also concluded (1942) that the types of balance within different populations vaned. For example, in a naturally inbred population a good internal balance would probably exist, while large random breeding populatiolis would be characterized by a relatively higher amount of relational balance. SCHMALHAUSEN (1949) pointed out that the harmoniously balanced genotype can be disrupted by the introduction of chromosomes of a differently balanced system, and further, WRIGHT (1 952) discussed linked factors in terms of a balance among those genes that are fixed, or nearly fixed, in a population. I This investigation was supported by a grant from the U. S. Public Health Service, 2 Authorized for publication on May 20, 1960, as paper No. 2461 of the journal series of the
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.