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难句剖析

导读诱思

Much of what researchers learn about human disease comes from studying animal models such as mice.Often,animal models are genetically engineered to carry disease—causing changes in their genes.Creating these animals is a long process.Cloning technologies might reduce the time needed to make a transgenic1 animal model,and the result would be a population of genetically identical animals for study. Stem cells2 are responsible for developing and repairing the body throughout life.As a result,they might be used to repair damaged or diseased organs and tissues3.Researchers are looking on cloning as a way to create genetically engineered human stem cells for research and medical purposes.