Cloning is an experimental technique wherein a group of morphologically and genetically identical organisms are produced. The “Clone” is an organism derived from a single parent by asexual method. A clone may be defined as an exact carbon copy or copies of a single parent. The word clone refers only to living species.
Dolly was a cloned sheep, developed by Dr.Ian Wilmut
and his colleagues in Roselind Institute in Scotland in July 1996. The scientists used nucleus of udder cell (somatic cell taken from mammary gland) from a six year old Finn Dorset white sheep. The nucleus of the udder cell contains diploid number (2n) of chromosomes with all the genes. They preserved the diploid nucleus in a suitable preservative. Then they took an ovum from the ovary of another sheep. The haploid nucleus (n) in the ovum was removed.
The diploid nucleus of the udder cell was injected into the cytoplasm of the enucleated ovum. Then the ovum with the diploid nucleus, was implanted into the uterus of the surrogate mother sheep. Since the ovum had the diploid nucleus, it developed into a young clone. It was named “Dolly” by Dr.Ian Wilmut.