ABSTRACT
Phenotype and genotype At the dawn of genetics in 1865 Gregor Mendel made two fundamental discoveries. The first was that each gene is represented by two copies in an organism, and this conclusion was proven to be true for the vast majority of eukaryotic species. The second drew a distinction between the genetic constitution of an individual and the expressed traits. This conclusion was also supported by subsequent progress in genetics. In order to properly describe these observations the special terms gene and allele, as well as genotype and phenotype, were introduced by the Danish scientist Wilhelm Johannsen as early as 1905. William Batson, leading British scientist and a towering figure in the early twentieth century, independently introduced the terms gene and genetics at the same time.
