Abstract: At present,the ways of somatic cell nclear transfer(SCNT) was still the same to the Willadsen’s method: enucleation, injection, fusion and activation.With its low efficiency and requiring sophisticated and expensive micromanipulation equipment and considerable skills from the operator,so attempt to simplify and establish a cloing process suitable for manufacturing conditions,thereby improve the effieiency of nuclear transfer has been a tireless efforts of the people.This paper introduces the methods of zona-free SCNT and the single embryo culture system.

Key words: zona-free; SCNT; single embryo culture system