Designer Sperm Passes Selected Genes to Future Generations

Frustrated by slow progress in gene therapy, a team of scientists opted for an unconventional approach. Instead of relying on the oocyte as a substrate for genetic modification, they took a closer look at male germ cells, including mature sperm. Sperm, owing to their accessibility, seemed to offer a convenient route to transgenesis.

The scientists, based at the Royal Veterinary College in North Mimms, United Kingdom, used a viral vector to insert genetic material into mouse spermatozoa. Then the spermatozoa were used in an in vitro fertilization procedure. In the resulting embryos, the genetic material was found to be present and active—and inheritable. The genetic material that had been introduced to the spermatozoa was, the scientists confirmed, still functional after passing through at least three generations of mice.

The scientists presented their results December 2 in The FASEB Journal, in an article entitled “Efficient generation of transgenic mice by lentivirus-mediated modification of spermatozoa.” In this article, the authors wrote, “When pseudotyped lentiviral vectors encoding green fluorescent protein (GFP) were incubated with mouse spermatozoa, these sperm were highly successful in producing...