Genetically altered mice: phenotypes, no phenotypes, and Faux phenotypes

Area of Science:

• Genomics
• Laboratory Animal Science
• Immunology

Background:

• Phenotype is influenced by genetic, environmental, and infectious variables.
• Laboratory mice, despite being inbred, exhibit variable pathophysiologic characteristics.
• Mouse strain background characteristics can impact genomics research outcomes.

Purpose of the Study:

• To highlight the critical influence of genetic, environmental, and infectious factors on laboratory mouse phenotype.
• To emphasize the importance of well-defined genetic backgrounds and controlled environments in mouse genomics.
• To underscore the impact of infectious diseases on research validity and reproducibility.

Main Methods:

• Review of existing literature on factors influencing mouse phenotype.
• Analysis of variables introduced by different methods of creating mutant mice.
• Discussion of the prevalence and impact of infectious agents in mouse colonies.

Main Results:

• Background genotype significantly influences the phenotype of gene mutations.
• Different approaches to creating mutant mice introduce variables affecting phenotype.
• Infectious diseases, even silent ones, can significantly alter mouse phenotype and jeopardize research.

Conclusions:

• Genetically well-defined mice and robust quality assurance programs are essential for functional mouse genomics.
• Environmental and infectious disease control are critical for accurate and reproducible research.
• The rise in infectious agents in mouse colonies poses a significant threat to research integrity.