TAILIEUCHUNG - Báo cáo sinh học: "The ‘stem cell’ concept: is it holding us back"

Tuyển tập các báo cáo nghiên cứu về sinh học được đăng trên tạp chí sinh học Journal of Biology đề tài: The ‘stem cell’ concept: is it holding us back? | Journal of Biology Opinion The stem cell concept is it holding us back Arthur D Lander Address Center for Complex Biological Systems Department of Developmental and Cell Biology and Department of Biomedical Engineering University of California at Irvine Irvine CA 92697-2300 USA. Email adlander@ Abstract Developmental biology regenerative medicine and cancer biology are increasingly occupied with the molecular characterization of stem cells. Yet recent work adds to a growing body of literature suggesting that stemness cannot be reduced to the molecular features of cell types and is instead an emergent property of cell lineages under feedback control. Great concepts in science do not just happen. They evolve often along predictable lines. In an especially common scenario an orderly set of related observations leads scientists to postulate an abstract entity or class whose existence somehow explains those relationships. Later on the entity gets an unambiguous operational definition through the application of some generally accepted experimental test. Frequently in a third and final stage the experimental test is replaced by a set of concrete features typically physical that more efficiently if sometimes a little imperfectly characterize the concept. As an illustration of this progression consider the concept gene . The idea that inherited traits might be passed from parent to offspring through discrete units first led to abstract notions of some sort of unit of heredity . Later tests based on breeding and recombination allowed such a unit to be operationally defined in a rigorous if sometimes laborious way. Eventually alternative definitions based on the physical characteristics of genes began to supplant such tests so that most modern biologists now see genes as stretches of DNA with particular sequence characteristics which happen to control inheritance as opposed to units of heredity that happen to be instantiated in DNA . Evidence that this more physical .

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