Word: eggs
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...George Daley at the Children's Hospital in Boston, shows that Hwang's stem cell line contains the first human cells to be generated not through SCNT, but through a process called parthenogenesis, sometimes referred to as virgin birth, since development is sparked spontaneously from the egg alone, rather than from the union of egg and sperm. Parthenogenesis is always a risk during nuclear transfer, since the process involves extensive manipulation of the egg and its nucleus. At the time that Hwang's original paper was published in Science, stem cell researchers raised the possibility that the cells had been...
Daley's subsequent detailed genetic analysis of Hwang's stem cells have clearly established that they come from a single egg, putting to rest nagging questions about what, if anything, Hwang and his team had actually accomplished. It may not have been Hwang's original goal, but successful parthenogenesis is no small feat. If he had reported it in 2004, says Daley, stem cell research might be much further along today - and enjoying a better reputation. "If we had known three years ago that it was possible to generate stem cells through parthenogenesis, then we almost certainly would already have...
...nuclear transfer, stem cells are created by inserting the nucleus from a donor's cell, usually a skin cell, into an egg cell, whose DNA-containing nucleus has been removed. The new cell then starts to divide and produce stem cells. In some cases, however, through mistakes in the nuclear-transfer process, eggs may begin dividing on their own. And Hwang may have increased his chances of parthenogenesis by using the gentler, squeezing technique he pioneered to remove the egg's nucleus; the process may have actually left behind enough genetic material for the egg to spontaneously divide...
...find out whether Hwang's stem cells came from a single egg, Daley's team, which included leading researchers from England, Japan and Canada, conducted a whole-genome analysis of the DNA from Hwang's stem cell line. By analyzing tens of thousands of gene snippets on the cells' genomes, and comparing these signatures to those of the egg donor and of the skin cell donor, they were able to determine that the DNA fingerprint of the stem cells was consistent with that of the egg. "The genetic signature of a parthenote is very very obvious," says Daley. Because...
...risky approach. Over at AARP, Deborah Russell, director of workforce issues, says her organization enthusiastically supports an active, fulfilling retirement. But, she cautions, "we do not advocate spending your nest egg" on start-up costs. According to the Small Business Administration, two-thirds of new businesses fail within four years...