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Genetic Vasectomy instead of Surgery
The University of Basel's Centre for Transgenic Models (CTM) has developed a genetic engineering approach to breed infertile male mice, eliminating the need for surgical procedures to sterilize them under anesthesia.
Sterile mice are essential in research for the generation of transgenic mice, where researchers intentionally insert an additional gene, typically human, to study its function or understand a disease mechanism.
Researchers first grow a genetically modified embryo in a Petri dish, which is carried to term by a surrogate mother. The female is paired with a sterile male to induce a false pregnancy, and the formation of a vaginal secretion plug indicates successful mating and readiness to receive an embryo.
In the conventional method, male sterilization in mice is carried out through surgical vasectomy, which involves general anesthesia and causes moderate pain requiring painkillers. However, at the Center for Transgenic Models (CTM) at the University of Basel, researchers have developed an alternative approach using genetic engineering to breed infertile male mice without the need for surgery. The researchers modified the mice to overproduce a crucial protein essential for sperm development, which results in complete sterility but does not affect mating or the formation of the secretory plug in the female.
The protein overproduction is heritable, allowing the breeding of sterile males from females carrying the gene. Furthermore, the researchers linked the gene responsible for sterility to a genetic marker that causes the carriers of the gene to fluoresce green. This makes it easy to identify mice that carry the gene for sterility without the need for invasive procedures.
The CTM now employs these genetically sterilized male mice as standard in the generation of transgenic mice, eliminating the need for invasive and stressful surgical vasectomy. Additionally, their work puts an end to the stressful single housing of vasectomised male stud mice by showing that their permanent co-housing with female mice does not impair the vasectomised stud male performance.
In recognition of his work, Pawel Pelczar, the head of CTM, received the 2019 3R Prize of the International Society for Transgenic Technologies (ISTT) for successfully implementing group housing of otherwise individually kept vasectomized males at CTM.
