10 February 2002
CLONED ANIMALS MEET EARLY DEATHS
"Is not our entire life marked by Godís kindness? The beginning of life
and its marvelous development: this is a gift. And because it is gift,
life can never be regarded as a possession or as private property, even
if the capabilities we now have to improve the quality of life can lead
us to think that man is the "master" of life. The achievements of medicine
and biotechnology can sometimes lead man to think of himself as his own
creator, and to succumb to the temptation of tampering with "the tree of
life" (Gn 3:24). It is also worth repeating here that not everything that
is technically possible is morally acceptable."
MESSAGE OF THE HOLY FATHER POPE JOHN PAUL II FOR LENT 2002 on the text: "You received without paying, give without pay" (Mt 10:8)
Cloned animals meet early deaths
From the New Scientist, 10 February 02
Cloned animals may indeed die young suggests the first direct study of their lifespan, carried out by Japanese researchers on mice.
Cloning involves removing the nucleus from an egg and replacing it with the nucleus of a donor cell. Many of these "nuclear transfer" embryos never develop or [they] miscarry. Even after birth some clones die. But many cloning scientists argue that the few survivors can be perfectly normal.
Atsuo Ogura of the National Institute of Infectious Diseases in Tokyo says his team's work suggests that some effects of cloning are not apparent in the days, weeks or even years after birth. "It is very probable that, at least for some populations of clones, some unpredictable defects will appear in the long run," he says.
The debate over the health of clones and how they age has swung one way and then the other. In November 2001, US biotech company Advanced Cell Technology reported the cloning of two dozen apparently healthy cloned cows. But in January, the first mammal cloned from an adult cell, Dolly the sheep, was reported to have prematurely developed arthritis.
Rudolf Jaenisch, a mouse cloner at Massachusetts Institute of Technology in Boston says the new work "shows that to look at animals at one point in time and say they are healthy and normal is really wishful thinking."
Immune system defect
Ogura's team cloned 12 male mice and these were compared with seven males from natural matings and six others produced using in vitro fertilisation. The clones appeared active and healthy, gained weight normally and matched the control animals in 14 of 16 physiological measurements.
But the first cloned animal died after only 311 days and, by day 800, 10 (83 per cent) of the animals were dead. In contrast, only three (23 per cent) of the controls died during the same period.
The dead clones showed high rates of pneumonia, liver disease, cancer and a lower level of antibody production, suggesting they had an immune system defect. Ogura's team is now trying to pinpoint the precise cause of death and repeat the experiment with more animals.
ACT's Tony Perry points out that it remains unclear if clones from other species such as cows or pigs die early. And even if clones in general do prove to have a shortened lifespan, he does not think that undermines data from ACT and others that clones can be healthy.
All the researchers agree that the work should be an additional warning to would-be human cloners.
Journal reference: Nature Genetics (DOI: 10.1038/ng841) 19:00 10 February 02
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