Scientists Develop First ‘Knock-Out’ Rat

Tuesday, May 20th, 2003

While scientists have been using “knockout” mice for years, Scientists Develop First ‘Knock-Out’ Rat reports that they’ve finally created “knockout” rats lacking BRCA-1 and BRCA-2, two genes thought to suppress the growth of breast cancer:

To produce knock-out mice, researchers simply need to collect embryonic stem cells, remove the gene of choice and then allow the stem cells to develop into a mouse, Gould explained.

This technique doesn’t work with rats, he explained.

To create knock-out rats, Gould and his colleagues injected male rats with a chemical that causes mutations in the stem cells of the testes, Gould said. Sperm that are formed after the injections will be missing a variety of genes, he added.

When the injected rats are bred with normal rats, their offspring end up with multiple genes knocked out, Gould said. “Each one of these offspring will have about 20 to 30 out of about 30,000 genes knocked out.”

Gould and his colleagues next devised a test to figure out which genes are knocked out in the offspring.

“So if you screen a thousand rats, maybe one will be the mutation you’re looking for,” Gould said. “Then this rat can be used for biomedical research.”

So they’re generating thousands of mutant rats, then screening out the small fraction with the right mutations? Hey, what could go wrong?

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