Murine physiology: measuring the phenotype.

The phenotype is the observable and measurable characteristic (or biochemical trait) of an organism that results from the interaction of the environment with the expression of gene alleles (i.e. the genotype). Accurate phenotyping demands that findings are not missed, anticipated, or biased; a mixture of assays that characterize distinct, but interrelated aspects of the cardiovascular phenotype are often necessary to meet these requirements. Such stringent conditions are crucial because it is phenotypic analysis that ultimately determines the utility of genetically altered and spontaneous mutant mice for biomedical research.