List the birth process of cloned sheep.

first step

Breast cells were taken from the breast of a 6-year-old Dorset white-faced ewe (A for short) in Finland and put into low-concentration nutrient medium, and the cells gradually stopped dividing. Such cells are called "donor cells".

Second step

An unfertilized egg cell was taken from the ovary of Scottish black-faced ewe (B) and enucleated immediately, leaving a seedless egg cell called "recipient cell".

Third step

Donor cells and recipient cells are fused by electric pulse method, and finally a "fused cell" is formed. Electrical pulses can produce a series of reactions similar to those in natural fertilization, so that the fused cells can divide and differentiate like fertilized eggs, thus forming "embryonic cells".

Fourth step

Embryonic cells were transplanted into the uterus of another Scottish black-faced ewe (C), and the embryonic cells further differentiated and developed, eventually forming Dolly sheep.

cloning technology

Cloning technology does not require male and female mating, and does not require the combination of sperm and eggs. It only needs to extract single cells from animals, cultivate them into embryos by artificial methods, and then implant the embryos into female animals to breed new individuals. This cloned animal cultured with single cells has exactly the same characteristics as the single-cell donor and is a "replica" of the single-cell donor.

Scientists in Britain and Oregon have successively bred Dolly the cloned sheep and Dolly the cloned monkey. The success of cloning technology is called "historic event and scientific innovation". Some people even think that cloning technology can be compared with the advent of the atomic bomb that year.