Detailed information about the French INRA research about the identification of long-lasting defects associated with somatic cell cloning of animals can be found at the website of The Lancet. Before you can look here, you'll have to register first (which does not mean you have to subscribe). You'll get to the regsitration page through http://www.thelancet.com
Below you find a press release from the Lancet about htis issue.
CLONING MAY CAUSE LONG-LASTING HEALTH PROBLEMS (p 1489)
Volume 353, Number 9163 1 May 1999
In February, 1997, researchers in Scotland made history when they reported that they had successfully cloned a sheep, named Dolly, with DNA from a mammary cell of an adult ewe. Before Dolly, animals had been successfully cloned but these clones were made with the DNA from cells of embryos. DNA from embryos is little changed from the DNA of a fertilised egg cell. DNA from an adult cell, on the other hand, such as that used to create Dolly, is altered because as a cell matures and specialises some of its genes are turned "off" and others "on". Indeed, before Dolly many scientists believed it would be impossible to make a clone with DNA taken from an adult cell because it would require that the cell's genes be reprogrammed, or reset, back to the na´ve embryonic state. The birth of Dolly raised the possibility that adult human beings could be used to make genetically identical clones of themselves, a prospect that raises many troubling ethical issues. But in this week's Lancet, French researcher Jean-Paul Renard and co-workers report that a cow cloned with DNA from an adult cell may have died because of errors in its DNA's genetic reprogramming. Although there have been many reports of clones dying during pregnancy or shortly after birth, this is the first report that indicates that cloning may have long-term harmful effects on the clone.
In the study, the researchers made a clone with the DNA from a cell taken from the ear of an adult cow, which was itself an embryonic clone. The researchers report that 1 month after birth, the calf's lymphocytes (an important class of white cells involved in the body's immune system) and its red blood cells decreased in number dramatically. The calf died shortly thereafter. A necropsy found that the lymphoid tissues-the thymus, spleen, and lymph nodes-had failed to develop normally. The researchers suspect that some part of the cloning process interfered with the clone's genetic reprogramming and prevented the normal development of the lymphoid system. The finding, the researchers write, indicates that cloning may cause long-lasting health problems in the clones.
Contact: Dr Jean-Paul Renard, UnitÚ de Biologie du Developpement, Laboratoire de Biologie Cellulaire et MolÚculaire, Institut National de la Recherche Agronomique, 78352, Jouy-en-Josas, France; tel +33 (0)34652594; fax +33 (0)134652677; e-mail email@example.com
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