Gene dosage and gene duplication

Everyone knows that gene duplications are of paramount importance for the emergence of new genes and new gene functions. Over the past century, many formal and verbal theories have been put forth to describe the process of evolution of new functions through gene duplications. More recently, completely sequenced genomes yielded the necessary data to start testing the theoretical expectations. We strive to understand the early stages in the life of gene duplications, and what forces, neutral or selective, lead to the fixation of a new gene copy. In essence, we try to understand what factors turn copy number variants (copy polymorphisms) into fixed gene duplications. We have found that recently fixed gene duplications preferentially code for dosage-sensitive functions that may be involved in organism-environment interactions, such as stress response, nutrient limitation or organic and inorganic toxicity response. To describe this phenomenon, we have unified the classic theory of genetic dominance first postulated by Sewal Wright with the theory of gene duplications. We postulate, that gene dosage plays an important role in the fixation and early maintenance of gene duplications, and probably is the basis of different frequencies of copy number variants in various populations.