The intermingling of the characteristics of the parents so that the offspring are intermediate in form between their parents. It is usually seen when a characteristic is controlled by many genes, as for example, height or yield. If a characteristic is governed by a single gene then blending inheritance is only seen when the alleles show *incomplete dominance
. It was thought that all characteristics become blended in the offspring. Until the rediscovery of Mendel's work this was the main criticism of Darwin's theory of evolution by natural selection, for the variation upon which it depended would always be lost by such a process. Mendel's demonstration of the particulate nature of inheritance removed this obstacle.