User:JillPill09/Somatic cell nuclear transfer

Early 20th-Century
Although Dolly the sheep is typically recognized as the first animal to be cloned using this technique, earlier instances of SCNT exist from the 1950's. The research of Sir John Gurdon in 1958 entailed the cloning of Xenopus laevis utilizing the principles of SCNT. In short, a female specimen was induced to ovulate, at which point her eggs were harvested. From here, the egg was enucleated, not with a needle, but with ultra-violet irradiation in order to disable the egg's pronucleus. At this point, the prepared egg cell and nucleus of the donor cell were combined, and then incubation and eventual development of the embryo into a tadpole proceeded. Gurdon's application of SCNT differs from more modern applications and even applications used on other model systems of the time (i.e., Rana pipiens) due to his usage of UV irradiation as opposed to removal of the egg's nucleus with a pipette.