Sheep named Dolly was cloned by transfer of a nucleus from a mammary (Udder) cell of an adult sheep into an egg cell. mammary cell Nucleus insert into a egg cell First demonstration of pluripotency (totipotency) of a nucleus of a differentiated adult cell. Cloning of dolly somatic cell nuclei clone cattle, sheep, goats, pigs. nuclear transfer procedures are similar. Adult donor cells from a variety of cell types(mammary epithelial and ovarian cells, fibroblasts, lymphocytes) are isolated Cultured and genetically modified methods. individual donor cells are fused to an enucleated oocyte with short-duration electric pulse. eg: two 2.5 kilovolt /cm pulses for 10microseconds Used to fuse adult cattle fibroblasts with enucleated oocytes. The pulses simultaneously induce cell fusion and oocyte activation. Blastocyst stage before transferred into the uterus of a pseudopregant female. Confirmed transgene at the time of birth Surviving animals produced by nuclear transfer are healthy. There, is a substantial loss of individual before and after birth some of the cloned animals display abnormalities. Abnormlities such as increased birth weight. Dna methylation and histone modification of the original donor cell is inappropriate maintained in the cells of the recipient animals.