New method for producing transgenic mammals

Embryologists at the University of Hawaii School of Medicine have reported a new method of producing transgenic animals. Dubbed 'Honolulu transgenesis', the technique is a modification of a method originally developed by Ryuzo Yanagimachi for injecting sperm into eggs. Called intracytoplasmic sperm injection (ICSI), this microinjection technique is fast becoming a standard practice in IVF (in vitro fertilisation) for the treatment of male infertility.

In this experiment, the Hawaii team, whose members made headlines last year with the cloning of mice, first treated mice sperm to disrupt their coat after which the sperm were mixed with DNA. The sperm and the DNA were then injected into mouse eggs and developing embryos were transferred to a surrogate mother.

Subsequent tests showed that in one in five of the resulting offspring, every cell contained the introduced DNA. The researchers hope that the technique will be useful in medical research and in the development of xenotransplant donors.