Knock em out
With increasing use of knockout mice for biomedical experiments, the surrounding ethical debates are brought into sharp focus. Toby Reynolds investigates
After falling steadily for decades, laboratory use of animals is increasing again-and not just in the United Kingdom. Behind the change is a huge increase in the genetic modification of mice, driven by the desire to make sense of the recently sequenced human genome and to understand disease better. The past two years have seen the start of several multimillion dollar projects to generate and characterise thousands of new strains of genetically altered mice. Ultimately, researchers aim to generate as many as one mutant line for each of the 25,000 odd genes in the mouse genome.
“Now that the whole mouse genome and other genomes are known, the question is, ‘What [are] the functions of all these genes?’” said Eckhard Wolf, professor of animal breeding at the University of Munich. “The best way to find these functions out is to have multiple alleles, different forms of each gene, and to