Phenotypic Trait - Definition

Definition

A phenotypic trait is an obvious and observable trait; it is the expression of genes in an observable way. An example of a phenotypic trait is hair color, there are underlying genes that control the hair color, which make up the genotype, but the actual hair color, the part we see, is the phenotype. The phenotype is the physical characteristics of the organism. The phenotype is controlled by the genetic make-up of the organism and the environmental pressures the organism is subject to.

A trait may be any single feature or quantifiable measurement of an organism. However, the most useful traits for genetic analysis are present in different forms in different individuals.

A visible trait is the final product of many molecular and biochemical processes. In most cases, information starts with DNA traveling to RNA and finally to protein (ultimately affecting organism structure and function). This is the central dogma of molecular biology as stated by Francis Crick.

This information flow may also be followed through the cell as it travels from the DNA in the nucleus, to the cytoplasm, to the ribosomes and the endoplasmic reticulum, and finally to the Golgi apparatus, which may package the final products for export outside the cell.

Cell products are released into the tissue, and organs of an organism, to finally affect the physiology in a way that produces a trait.