Explain the creation of Dolly .

Explanation

(i) Dolly was the first mammal (Sheep) clone developed by lay Wilmut and Campbell in 1997. Dolly, the transgenic clone was developed by the nuculear transfrer technique and the phenomenon of totipotency. Totipotency refers to the potential of a cell to develop different cells, tissues , organs and finally an organism.

The mammary gland udder cells (somatic cells) from a donor sheep (ewe) were isolated and subjected to starvation for 5 days. The under cells could not undergo normal growth cycle, entered a dormant stage and became totipotent. An ovum (egg cell) was taken from another sheep (ewe) and its nucleus was removed to form an enucleated ovum. The dormant mammary gland cell/uder cell and the emucleated ovum were fused. The outer membrane of the ovum to envelops the nucleus. The fused cell was implanted into another ewe which served as a surrogate mother . Five months later dolly was born . Dolly was the first animal to be cloned from a differentiated somatic cell taken from an adult animal without the process of fertilization.