Scientists from the state of Oregon in the USA report success in transplanting jellyfish genes into monkey embryos, through the application of a technique that in the future may be used to create monkeys into whose genetic structure human genes will be inserted. Such a technique will make it possible to study those genes and develop innovative treatment methods for human diseases.
By Gina Coletta, The New York Times Service
The scientists say they are aware that their research raises troubling questions about reproductive technology. If the scientists can add genes to monkey embryos, it is likely that they will be able to repeat the process in human embryos as well, an action that raises the emotionally charged issue of genetic engineering in humans.
According to some experts, what stands out in the study is the simplicity of the method. If perfected to be effective in monkeys, the day may not be far when scientists can add genes to human embryos as well. Certain genes may cure diseases or prevent them - such as a gene that is resistant to AIDS, or one that will reduce a person's chances of getting Alzheimer's. Adding such genes would be akin to vaccinating a child. Adding other genes may be more problematic.
Dr. Inder Verma, a molecular biologist from the Salk Institute in San Diego, describes in this context the gene that is responsible for the production of the protein that is used as a conductor for glutamate in the brain, and may improve memory. "Imagine that you insert a glutamate receptor supplement and activate it before you give it to a test monkey," he said. According to him, he is comforted by the thought that there would be very few people who could afford to undergo this type of genetic engineering, and that few of those would even want it.
According to experts, the research of the scientists from Oregon which is published in the latest issue of the magazine "Molecular Human Reproduction" is a kind of display of purpose. To add genes to the monkey embryos, Dr. Gerald Schatten and his colleagues from the Mammal Research Center at the University of Oregon in Beaverton began to make contact between jellyfish genes and sperm cells of rhesus monkeys. The genes were naturally attached to the outside of the sperm cells.
In the next step, the scientists tried to use the same sperm cells to fertilize eggs, and see if the genes of the jellyfish would become part of the developing embryos. The gene added to the sperm cells contained the genetic code that gives the jellyfish its glowing green color. If the gene is taken up in the monkey embryos, the embryo cells should produce a greenish glow when fluorescent lighting is placed over them.
One of the experiments conducted by the scientists included the fertilization of 81 eggs by direct injection of the sperm containing the jellyfish gene. When the scientists shined a light on the embryos that developed as a result of the fertilization, the result was unequivocal: "More than a third of the embryos glowed," said Dr. Schatten.
The scientists tried to use seven "luminous" embryos to create pregnancies. In the end, they only received a pair of stillborn twins, and another male monkey in which no evidence was found that the gene had been integrated into his cells. Despite this, the researchers have no doubt that the method will work, because it was recently successfully tested on mice.
Earlier this year, Dr. Ryuzo Ningimachi of the University of Hawaii reported on an identical experiment. 11 of the 57 mice born carried the gene from the jellyfish: when the tips of their tails were examined under fluorescent light, the cells glowed green. According to Yingimachi, although he is disappointed that the first monkeys did not carry the extra gene, "it's only a matter of time before we can."
According to Dr. Schatten, the use of monkeys is of great value in research on genetic defects in humans. "But when you think about their value as a model for diseases or for understanding cognition or for learning about diseases and defects that appear in humans, this is a very small first step."
{Appeared in Haaretz newspaper, 24/12/1999{
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