Word: mammalian
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...those applications - the recombinant DNA technique - has begun to fulfill its widely her alded promise. By inserting genes into the DNA of a laboratory strain of the common intestinal bacterium E. coli, re searchers have induced the little bug to produce somatostatin, a mammalian brain hormone. Last month the bacterium manufactured synthetic human insulin, raising hopes that the hormone vital to the well-being of the world's diabetics may some day soon be available in virtually unlimited supply...
...until the mid-1960s did researchers learn how to fertilize mammalian eggs in vitro on a regular basis. The groundwork was laid by M.C. Chang of the Worcester Foundation for Experimental Biology in Shrewsbury, Mass., and C.R. Austin of Cambridge University, who had solved the problem of in-vitro capacitation of rabbit sperm, a process that enabled sperm to penetrate the egg in the laboratory. Until then, the sperm were notably ineffectual in that role. But these early successes 'involved creatures no higher than rabbits, hamsters and mice...
...Gurdon experiments still represent the high-water mark of traditional cloning technique. Researchers find 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...
Bromhall says he first heard of Rorvik in May 1977, when the author wrote to him saying, "I am working on a new book and wish to discuss in it some of the prospects of mammalian cloning." Bromhall promptly replied with a nine-page abstract of his doctoral thesis on cloning. But when Image was published, Bromhall found to his great surprise that the birth of the cloned boy had supposedly occurred five months before the date of Rorvik's letter. "If Rorvik's story were true," says Bromhall, "then by the time he wrote...
...could pose. Last week scientists testifying before a Senate subcommittee lent strong support to that argument. They revealed that a group of California researchers has spliced a man-made gene into a bacterium, and then, for the first time, used the altered microbe to make a copy of a mammalian brain hormone that can act biologically in humans. The accomplishment brought closer the day when scarce and costly hormones and enzymes needed for treatment of genetic disorders can be produced inexpensively and on a large scale...