Phenotype

The phenotype or appearance is in genetics, the amount of all the characteristics of an organism. It refers not only morphological but also the physiological and psychological characteristics.

The phenotype is determined by the interaction between genetic and environmental factors ( modification). The extent to which the phenotype is influenced by environmental influences, dependent on the reaction standard. This ability to respond to environmental influences, is genetically determined.

Phenotypic plasticity

If environmental factors can cause a strong variability in the appearance of an individual, it is called phenotypic plasticity high or wide range of variation or modifiability. Is the phenotype but largely predetermined by its genotype, this indicates low plasticity. The concept of phenotypic plasticity describes the degree to which the phenotype of an organism is previously determined by its genotype. A high value of plasticity means that environmental factors have a strong influence on the individually evolving phenotype. At low plasticity of the phenotype can be reliably predicted from the genotype, regardless of special environmental conditions during development. High plasticity can be observed on the example of the larvae of two species of newts: If these larvae perceive the presence of predators such as dragonflies, the head and the tail larger in proportion to body and skin pigmentation is darker. Larvae with these features have better chances of survival against predators, but grow more slowly than other phenotypes. Phenotypic changes due to environmental influences are called modifications. Thus (for example cuttings ) develop at different sites completely different growth forms, for example, genetically identical plants.

Phenocopy

Does an exogenous (not hereditary ) factor in a certain period of development in the fetus, it can cause deformities that can mimic the phenotype of genetic disorders or syndromes. In this case one speaks of phenocopy.

If a particular phenotype may come from different genetic aberrations, it is called heterogeneity.

Drama Type

Particularly in the biomedical field, the model of the phenotype of Russel / Burch in 1951 expanded to include the drama type. This represents the response to the immediate, instantaneous environment, while developing the phenotype refers to a longer period. The knowledge about the drama type is necessary to obtain a uniform result possible in animal experiments.