Gregor Johann Mendel

In Darwin's time, biologists held to the theory of blending inheritance -- an offspring was an average of its parents. If an individual had one short parent and one tall parent, it would be of medium height. And, the offspring would pass on genes for medium sized offspring. File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ... File history Legend: (cur) = this is the current file, (del) = delete this old version, (rev) = revert to this old version. ...

 If this was the case, new genetic variations would quickly be diluted out of a population. They could not accumulate as the theory of evolution required. 

Historically, this was a short-lived 19th century "arm-chair" biological theory of inheritance, primarily discredited by the experiments of Gregor Mendel. It is similar to the modern idea of incomplete dominance in that the offspring will express a blending of the different traits of the parents. However, while incomplete dominance only expresses this blending in the phenotype, keeping the alleles within the heterozygote distinct (and, thus still inheritable in successive generations), the theory of blending inheritance referred to an actual blending of the genetic material (i.e. in modern terms, alleles would blend together to form a completely new allele). The offspring's trait, from parents with differing traits, in theory, could express itself exactly like either trait from one of the two parents or could express itself as some intermediate mixing of the parental traits. This blending theoretically was a smooth spectrum of infinite possible outcomes. This theory works similar to the way paint mixes. And, like with paint, where two colors, once mixed, become unrecoverable via successive mixing with still other colors, the historical theory of incomplete dominance required that at least half of all genetic variances to be completely unrecoverable in successive generations.) Gregor Johann Mendel (July 20, 1822[1] – January 6, 1884) was a Moravian[2] Augustinian priest and scientist often called the father of modern genetics for his study of the inheritance of traits in pea plants. ... It has been suggested that this article or section be merged with dominance relationship. ... It has been suggested that this article or section be merged with dominance relationship. ... Individuals in the mollusk species Donax variabilis show diverse coloration and patterning in their phenotypes. ... An allele is any one of a number of alternative forms of the same gene occupying a given locus (position) on a chromosome. ... An organism is a heterozygote or heterozygous for a gene or trait if it has different alleles at the genes locus for each homologous chromosome. ... An allele is any one of a number of alternative forms of the same gene occupying a given locus (position) on a chromosome. ... For the hard rock band, see Allele (band). ...