Phene

A phene is an individual genetically determined characteristic or trait which can be possessed by an organism, such as eye colour, height, behavior, tooth shape or any other observable characteristic.

The term 'phene' was evidently coined as an obvious parallel construct to 'gene'. Phene is to Phenotype as Gene is to Genotype, and Similarly Phene is to Phenome as Gene is to Genome. More specifically, a Phene is an abstract concept describing a particular characteristic which can be possessed by an organism. Whereas Phenotype refers to a collection of Phenes possessed by a particular organism, and Phenome refers to the entire set of Phenes that exist within an organism or species.

Genome wide association studies use "phenes" or "traits" (symptoms) to distinguish groups in the human population. These groups are then employed to identify associations with genetic alleles that are more common in the symptomatic group than in the asymptomatic control group. Allen et al. report that with respect to Schizophrenia "Research in molecular genetics has focused on detecting multiple genes of small effect" This indicates the importance of discovering individual traits or "phenes" that are governed by single genes. Schizophrenia or bipolar disorder may be described as a phenotype but how many individual traits or "phenes" contribute to these phenotypes? Very large genome wide association studies have not found many significant gene linkages. On the contrary the results of these studies implicate a large number of gene alleles that have a very small effect (phene).

It is important to note that the word phenotype was originally used to refer to both the trait/character itself (e.g. the blue eyes phenotype) and the set of traits/characteristics possessed by the organism (clair's eye-colour phenotype is blue). While this definition is still used in many places, the lack of distinction can make indepth explanations confusing and thus use of the term Phene becomes necessary. Indeed, it is extremely difficult to determine precisely what the fundamental building blocks of a phenome are. Since the term "phenotype" has been used to describe traits and syndromes and population characteristics it is not helpful in the collective search for specific traits that could be a consequence of a single gene or gene-environmental interaction. Phene has emerged as a candidate building block for the phenome.

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