Word: developable
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Dates: during 1970-1979
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...differentiated. U.S. Biologists Robert W. Briggs and Thomas J. King confirmed this principle and pioneered the basic technique of animal cloning in the early 1950s. They removed the nuclei of unfertilized egg cells from female frogs. These nuclei were then replaced with nuclei taken from the cells of developing frog embryos, which at this early stage were merely clumps of cells that had not yet differentiated into specific organs. Some of the frog eggs, with their newly implanted nuclei, acted as if they had been fertilized; they started to divide and went on to develop into tadpoles...
...that cloning mammals is a much more complicated affair. For one thing, mammalian eggs are one-tenth to one-twentieth the size of frog eggs and thus difficult to manipulate. And while tadpoles grow into frogs in a pond (and therefore easily in a laboratory tank), mammalian embryos must develop in a womb...
...Using microsurgery, Markert removes either pronucleus. The egg is then exposed to a chemical that causes the remaining pronucleus to replicate, thus giving the cell a full complement of genes. Then the cell itself divides, and the resulting embryo is placed in the uterus of a female mouse to develop. Using this technique, Biologist Peter C. Hoppe of Jackson Laboratory in Bar Harbor, Me., and Swiss Microsurgeon Karl Illmensee have produced seven mice, all females. (Males cannot be produced by this method because the male and female pronuclei never merge, making it impossible for the male XY chromosome combination...
...this point in his life, Carlin must face the problem of growth. For an artist to continue art, he must develop ceaselessly and elude decadence. But as he gets older and most of his self expression becomes already expressed, Carlin's importance as a teller of irony pales. He kicks inadvertantly at the posh golden carpeting under his feet at the Pierre...
...executive of the state-run British National Oil Corp. was convinced that there is a huge lode of oil in the Shetlands area, but agreed with other petroleum experts that it would take several years to develop the technology to exploit it. Reason: initial samples show it to be much heavier and more viscous than North Sea oil, and therefore more expensive to raise and refine...