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Gene therapy and gene-based drugs are two ways we could benefit from our growing mastery of genetic science. But there will be others as well. Here is one of the remarkable therapies on the cutting edge of genetic research that could make their way into mainstream medicine in the coming years.
While it's true that iust about every cell in the body has the instructions to make a complete human, most of those instructions are inactivated, and with good reason: the last thing you want for your brain cells is to start churninq out stomach acidor your nose to turn into a kidney. The only time cells truly have the potential to turn into any and all body parts is very early in a pregnancy,when so called stem cells haven't begun to specialize.
Yet this potential could be a terrific boon to medicine. Most diseases involve the death of healthy cells--brain cells in Alzheimer's, cardiac cells in heart disease, pancreatic (胰腺的) cells in diabetes (糖尿病), to name a few;if doctors could isolate stem cells, then direct their growth, they might be able to furnish patients with healthy replacement tissue.
It was incredibly difficult, but last fall scientists at the University of Wisconsin managed to isolate stem cells and get them to .grow into neural,gut, muscle and bone cells. The process still can't be controlled, and may have unforeseen limitations; but if efforts to understand and master stem cell development prove successful, doctors will have a therapeutic tool of incredible power.
The same applies to cloninq, which is really lust the other side of the coin;true cloning, as first shown with the sheep Dolly, involves taking a developed cell and reactivating the genome within, resetting (重新设定) its developmental instructions to a pristine state. Once that happens, the cell can develop into a full fledged (羽毛丰满的) animal, genetically identical to its parent.
For agriculture, in which purely physical characteristics like milk production in a cow have real market value, biological carbon copies could become routine within a few years. This past year scientists have done for mice and cows what lan Wilmut did for Dolly, and other creatures are boundto join the cloned menagerie in the coming year.
Human cloning, on the other hand, may be technically feasible but legally and emotionally more difficult. Still, one day it will happen. The ability to reset body cells to a pristine, undeveloped state could Qive doctors exactly the same advantages the would et from stem cells: the potential to make healthy body tissues of all sorts, and thus to cure disease. That could prove to be a true "miracle cure".