British scientists say they have created human embryos containing DNA from two women and a man in a procedure that researchers hope might be used one day to produce embryos free of inherited diseases.
Though the preliminary research has raised concerns about the possibility of genetically modified babies, the scientists say that the embryos are still only primarily the product of one man and one woman.
"We are not trying to alter genes, we're just trying to swap a small proportion of the bad ones for some good ones," said Patrick Chinnery, a professor of neurogenetics at Newcastle University involved in the research.
SNIP
The genes being replaced are the mitochondria, a cell's energy source, which are contained outside the nucleus in a normal female egg. Mistakes in the mitochondria's genetic code can result in serious diseases like muscular dystrophy, epilepsy, strokes and mental retardation.
In their research, Chinnery and colleagues used normal embryos created from one man and one woman that had defective mitochondria in the woman's egg. They then transplanted that embryo into an emptied egg donated from a second woman who had healthy mitochondria.
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Full ArticleMars is unlikely to sport beachfront property anytime soon, but the planet has enough water ice at its south pole to blanket the entire planet in more than 30 feet of water if everything thawed out.
With a radar technique, astronomers have penetrated for the first time about 2.5 miles (nearly four kilometers) beneath the south pole's frozen surface. The data showed that nearly pure water ice lies beneath.
Discovered in the early 1970s, layered deposits of ice and dust cap the North and South Poles of Mars. Until now, the deposits have been difficult to study closely with existing telescopes and satellites. The current advance comes from a probe of the deposits using an instrument aboard the Mars Express orbiter.
"This is the first time that a ground-penetrating system has ever been used on Mars," said the new radar study's lead author, Jeffrey Plaut of NASA's Jet Propulsion Laboratory. "All the other instruments used to study the surface of Mars in the past really have only been sensitive to what occurs at the very surface."
(NASA's Mars Odyssey spacecraft also carries instruments designed, among other things, to probe beneath icy polar surfaces.)
Deep probe
Plaut and his colleagues probed the deposits with radar echo sounding, typically used on Earth to study the interiors of glaciers. The instrument, called the Mars Advanced Radar for Subsurface and Ionospheric Sounding, or MARSIS, beams radio waves which penetrate the planet's surface and bounce off features having different electrical properties.
The reflected beams revealed that 90 percent or more of the frozen polar material is pure water ice, sprinkled with dust particles. The scientists calculated that the water would form a 36-foot-deep ocean of sorts if spread over the Martian globe.
