The “No Phenotype” Challenge in Analyzing Mutant Mice
- 1Department of Genetics and Development, Columbia University Medical Center, New York, New York 10032, USA
- 2Department of Genetics, University of Texas MD Anderson Cancer Center, Houston, Texas 77030, USA
- ↵3Correspondence: vep1{at}columbia.edu
Abstract
If homozygous mutant mice survive to adulthood, are fertile, and have no visible phenotypes attributable to mutation of the relevant gene, there are a number of possible reasons why an effect of the mutation is not evident. Technical errors that might have occurred during gene targeting or genotyping must first be eliminated. Variable penetrance of the mutation should be considered as well as the possibility of age-related or late-onset phenotypes, such as tumor formation or other pathologies. The gene expression pattern and nature of the protein product of the gene could provide clues. A number of simple tests can be applied to uncover cryptic phenotypes that are not easily seen on casual inspection (e.g., tests of the senses and of balance and coordination). Genetic and environmental challenges can be applied to overtly normal mutant mice to reveal deviations from normal.
Footnotes
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From the Mouse Phenotypes collection by Virginia E. Papaioannou and Richard R. Behringer.
