The normal form of an organism as it is ordinarily encountered in nature. In contrast to natural mutant or laboratory mutant individuals (organisms). One example of a measurable difference between the two types is that wild strains of animals respond to the presence of EMF fields (e.g., weak magnetic fields such as those generated near power transmission cables), but laboratory strains of the same animals do not.
In genetics, the customary or usual phenotype used as a standard for comparison.