Oligogenic inheritance (Greek ὀλίγος – ὀligos = few, a little) is a concept introduced after it was learned that the model of inheritance of most of the previously described "monogenic traits" cannot validly explain the phenotype distribution in the offspring of certain types of reproductive couples. It may be noted that the exposed theory concept of monogenic control of the phenotypic traits based on the classic route: one gene – one feature. There is a small number of genes involved in the control of only one property, and it seems that even fewer features that are controlled by the alleles from only one locus.
Although the modern genetics does not know the genes that control the absolutely only one phenotypic trait (but, logically, not one that is determined by a single gene!), the corresponding literature will (probably) long many traits treated as monogenic.
Further studies, however, have shown that this simplification enough arguments to justify the prevailing view that the majority of monogenic features have oligogenic determination, or that such traits genetically certain small number of oligogenes with a very dominant phenotypic effect major gene; effect of other, so-called minor genes from the corresponding oligogenic series (as well as environmental factors) on the expression of the observed characteristics is, in fact, practically negligible. It should be noted, however, that the difference between major and minor genes, as well as criteria for separating the oligogenic and polygenetically feature is still arbitrary.
The term oligogene into the science of inheritance was introduced by Keneth Mather (1941).