A rchive Date
[ 29-09-2000 ]
Category
[ Science ]
sub-Categoy
[ Biotechnology ]
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[Cloning technology comes of age
By DAVID SUZUKI-- CNEWS Science
Friday, Sep. 29, 2000
Ever since the Soviet Union shocked the world in 1957 by launching Sputnik, the first human-made satellite, the rate of scientific progress in medicine, computer technology, telecommunications and biology has been astounding.
Nowhere are advances more spectacular than in genetics. My daughter, a third-year student in university, is doing experiments in her genetics course with DNA, the genetic material, that I never dreamed would be possible in my lifetime when I graduated with a PhD in genetics in 1961.
The great science writer, Isaac Asimov, once remarked in the 1970s that to estimate how far science will advance by the end of the century, take the wildest estimates, then double that and double it again. Nothing illustrates it better than cloning.
The concept is very simple. At fertilization, an egg and a sperm unite to form a cell containing all the information needed to make a complete individual. That cell will then divide numerous times, faithfully duplicating and passing on to all cells, all of the genetic information in the original fertilized egg. In a human adult, this comes to some 60 trillion cells, each one of which carries the entire genetic blueprints that were in the sperm and egg. Thus, in principle, every cell in our bodies contains all the genes needed to turn it into a full human being. This would be a clone of the person the cell comes from (clone comes from the Greek word meaning cutting - the way plants can be reproduced).
Cloning itself is not unnatural. Some micro organisms, including bacteria and yeast, naturally reproduce by cloning (asexual reproduction) rather than by sexual reproduction and many plants like strawberries and aspen clone naturally. Identical twins are clones of one cell, as were the Dionne quintuplets. Interestingly, armadillos always give birth to identical quintuplets.
The interesting question is whether a cell from an adult animal can be cloned. In 1932, Aldous Huxley anticipated the social potential of cloning humans in his classic book Brave New World. And ever since, popular movies and books like The Boys from Brazil about cloning Hitler and In His Image, a fictional book claiming a multibillionaire had cloned himself, have explored the explosive ramifications of cloning.
The first breakthroughs in modern cloning began in the late 1950s, when biologist John Gurdon cloned African clawed toads, Xenopus laevis, thus showing it could be done with a complex animal. Still, when I began to give public lectures in the 1960s and talked about cloning humans, I was admonished by my colleagues that it was so far on the horizon that I was needlessly alarming people.
Yet by the 1970s, fruit flies had been cloned and by the late 1980s, mammals like mice and rabbits had been successfully cloned. In the 1990s, scientists managed to clone sheep and even primates. Genetically, primates and humans aren't that much different, and with a lot of money and effort I have no doubt that a human could be cloned with techniques already in use.
Human cloning raises many ethical questions, but the process also has significant medical potential, including using our own cells to clone organs for ourselves, which could then be used to replace those that are damaged or diseased. This would negate one of the most dangerous aspects of organ transplantation - rejection of the donor by the host - because the donor organ would be genetically identical to the host.
But such techniques are still a ways off. As I will discuss in the next column, cloning is still in its infancy and there may be underlying biological constraints that prevent animals from being cloned through multiple generations.
 World Fact Book (CIA)]
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