LMB 365 – Day 66

This image for day 66 of #LMB365 shows a C57BL/6 mouse egg being fertilised by sperm from a genetically modified mouse, during an IVF (in vitro fertilisation). The spermatozoa bind to the outer membrane of the egg, often causing the egg to rotate as they attempt to penetrate it. This is sometimes known as the “fertilisation dance”. The LMB shares genetically modified mouse strains with other research establishments in the UK and around the world. In order to minimise the transportation of live mice, and limit any potential stress caused to the animals, cryopreserved sperm is often shared between establishments, rather than live mice. This is an example of 3Rs (Replacement, Reduction and Refinement). The LMB is committed to upholding the highest standards of animal welfare.