doi:10.1038/nindia.2008.223 Published online 16 June 2008
Answering the ethical question surrounding animal experiments, researchers in India have developed a technique that can make transgenic mice without the need for hundreds of mice eggs or sacrificing the animals post-experiment1.
The researchers from the National Institute of Immunology in New Delhi have developed a reproducible non-terminal technique for inserting genes in the testicular germ cells (spermatogonia) of mice through a process called in vivo electroporation or passing mild current for a fraction of a second.
Using different genes, the team has reported a success rate of about 94%. Most male mice electroporated with different transgenes successfully fathered transgenic pups. Such electroporated males provide a valuable resource for continuous production of transgenic founders for more than a year.
Since human beings can not be experimented upon, transgenic animals are popularly used in therapeutic development as well in the understanding of a disease. Human genes are used to develop such animals but the technology is expensive, labour-intensive, time-consuming and requires hundreds of eggs collected from several females for inserting foreign genes so that the babies born are transgenic.
"The complexities of the existing technology and need for several donor females have restricted generation of transgenic cattle," says lead researcher Subeer Majumdar. Transgenic cattle are important for generating human based drugs in their milk. Transgenic non-human primates are used as surrogates of certain human diseases such as AIDS, mental retardation, Alzheimer's and Parkinson's.
"With the availability of details of the complete human and mouse genomes, use of transgenic mice as a model is bound to increase," Majumdar says. Hence, there is an urgent need to develop an alternate, cost-effective and more rapid approach to obtain several desired transgenic founders with various genes, preferably with minimum or no loss of animal lives.
The present deathless technique can ensure that every biologist generates his own transgenic animals at low cost and without the help of specialized labs. Majumdar says cattles producing costly therapeutic agents through inserted human genes in the milk and macaque models of difficult human diseases can be made using the technique.