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5 December 2013 11:26 am ,
Vol. 342 ,
At age 30, Dutch biologist Freek Vonk has built up a respectable career as a snake scientist. But in his home country,...
Since arriving on the island of Guam in the 1940s, the brown tree snake ( Boiga irregularis ) has extirpated native...
An animal rights group known as the Nonhuman Rights Project filed lawsuits in three New York courts this week in an...
Researchers have been hot on the trail of the elusive Denisovans, a type of ancient human known only by their DNA and...
Thousands of scientists in the Russian Academy of Sciences (RAS) are about to lose their jobs as a result of the...
Dyslexia, a learning disability that hinders reading, hasn't been associated with deficits in vision, hearing, or...
Exotic, elusive, and dangerous, snakes have fascinated humankind for millennia. They can be hard to find, yet their...
Researchers have sequenced and analyzed the first two snake genomes, which represent two evolutionary extremes. The...
- 5 December 2013 11:26 am , Vol. 342 , #6163
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Look Mom, No Sperm!
31 January 2002 (All day)
A reproductive quirk of some reptiles, insects, and other species may help stem cell researchers sidestep ethical debates over the use of human embryos. In the 1 February issue of Science, researchers report they have isolated the first stem cell lines from primate parthenotes, embryos grown from unfertilized eggs that, in mammals, can't develop into viable fetuses.
In October, scientists at the Institute for Reproductive Medicine and Genetics in Los Angeles showed they could derive stem cells, which later developed into neurons, from mouse parthenotes. Then in November, Advanced Cell Technology (ACT) in Worcester, Massachusetts, grabbed headlines with the news that it had created human parthenotes--although the cell clusters died before reaching the blastocyst stage, well before stem cells could be extracted (ScienceNOW 26 November 2001).
Now, ACT's Jose Cibelli and colleagues relate that they have cultured a variety of cell types from stem cells taken from monkey parthenotes. The scientists treated 28 macaque ova with chemicals that prevent eggs from ejecting half their chromosomes--as they do when fertilized--and instead spur the eggs to begin dividing. Four eggs developed into blastocysts, and the team established the first stable stem cell line from a primate parthenote.
The implication is that the same could be accomplished in humans, says Don Wolf of the Oregon Regional Primate Research Center in Beaverton. But every mammal has its own quirks, notes developmental biologist Davor Solter of the Max Planck Institute for Immunobiology in Freiburg, Germany. "If you want to figure out how to make [parthenotes] in humans, you have to make them in humans."
Ethically, however, the option is attractive, says bioethicist Glenn McGee of the University of Pennsylvania in Philadelphia. Human parthenotes cannot develop to full-term babies, so researchers could avoid the problem posed by therapeutic cloning, in which a potentially viable embryo is created as a source of stem cells and then destroyed.
Wolf says parthenogenesis would actually be simpler than therapeutic cloning for producing genetically compatible material for a patient--at least one with oocytes. "Of course, with this approach," he adds, "you could not produce your own stem cells unless you could also provide your own eggs. Sorry, guys."