Third twin? ...not yet
IT SEEMED an incident straight out of the pages of science fiction. On February 23, a team of Scottish scientists announced under that they had created the first ever clone of an adult animal and introduced to the world a seven-month-old sheep called Dolly. The experiment may well be a milestone in the field of genetics if it withstands the acid glare of sceptics who doubt "if it is true". In cloning history, hoaxes have been discovered years after the announcement of "successes".
A clone is an organism that is genetically identical to its 'parent'. Mammals, which reproduce sexually, do not clone naturally, except in the case of identical twins. But as the environment, experiences and their own choices endow them with much individuality, even they are not really 'identical', say observers.
In July 1996, a team of scientists headed by Ian Wilmut of Edinburgh's Roslin Institute, took a single cell from an adult sheep's udder, turned it into an embryo, and then implanted it inside another sheep for fertilisation. The result: a hale and hearty carbon copy of the 'parent' sheep. The Edinburgh team had taken unfertilised eggs from the 'mother' sheep and removed all the DNA from them, leaving behind just the gutted cell with the nutrients and cellular machinery needed to foster embryo growth.
Under normal conditions, the genes that the scientists have been joined by genes from a sperm, providing the full set of DNA necessary to encourage embryo growth. Instead, the researchers artificially added into the eggs a full set a single mature cell of the same sheep. A spark of electricity was through the eggs to trigger a divisions.
After a few days, the resulting embryos were transplanted into the womb of another sheep. The five ewes thus born, were genetically identical to the 'mother' animal that had donated the DNA. Three of the five clones produced died two minutes after birth, while the fourth died within 10 days. Post mortem on the dead sheep revealed kidney and cardiovascular abnormalities.
Scientists have long since been trying to clone animals like frog and mouse, but without any luck. According to Wilmut, "They failed to recognise that the donor cell must first be treated with chemicals that reset that cell's biological clock in a way that leaves its DNA poised to divide anew."
The cloning has stirred a hornet's nest in the field of genetic engineering. Critics are questioning the delay of seven months in announcing Dolly's appearance and the fact that her 'mother' is no longer alive. Moreover, the experiment has brought to fore several uncomfortable socioethical issues. With critics giving reasons for not encouraging human cloning, Ken Follet's 'third twin' may still have to wait.
Philippe Vasseur, farm minister of France, reportedly spoke of folk monstrosities like six-legged chickens and sheep with eight feet appearing on the scene after Dolly. Then, there is the old fear of human clones, which is still the stuff of futuristic literature.
Research on human cloning with government lands is prohibited in the UK and certain other countries. And in the US, federal funds cannot be used to conduct human embryo research. US President Bill Clinton has already asked the 18-member National Bioethics Advisory Commission to consider whether federal policies relating to human embryo, research should be reconsidered in the light of the Scottish scientists' discovery. However, neither of these countries have any legal weapon to stop private research on cloning of other life forms.
One of the common fears is that the technology that has been used to produce Dolly may not perfect. Even if it could he made to work in human cells, a being produced in this manner may age Prematurely, fall victim to diseases faster than usual, or may have hampered fertility. Even the idea of creating an all perfect 'superhuman' does not catch the fancy of the critics. Therefore, the idea of a departure from the natural order of things is inviting debate and legislation.