At a time when human cloning is in the headlines, new research suggests the procedure is unlikely to produce healthy individuals. With a colleague from Hawaii, Rudolph Jaenisch, an MIT biology professor and faculty member at the Whitehead Institute for Biomedical Research, created mouse clones from embryonic stem cells. The pair wanted to find out why such animals tend to grow too large and have poor survival rates. Their surprising conclusion: the original cells were unstable “in culture” — that is, in a lab dish — and as a result the animals grown up from such cells often had abnormal gene activity. Not all the rodents involved died young; some survived to adulthood despite genetic defects, suggesting the robustness of genetic systems. But the finding raises doubts about the potential for using cloning to produce healthy organisms. Jaenisch, whose research partner was the University of Hawaii’s Ryuzo Yanagimachi, says the work suggests that “even apparently normal clones may have subtle alterations of gene expression that are not easily detected.”
For some patients in whom injury or disease affect the prefrontal cortex — the twin lobes behind the forehead that for many epitomize the idea of “the brain” — the result is serious memory problems and related symptoms. Scientists have assumed that that’s because the damage has affected the machinery of memory. MIT research, though, suggests the real problem may be the loss of the ability to apply the rules we use in thinking about or analyzing situations. Earl Miller, an associate professor of brain and cognitive sciences, and his co-workers taught monkeys to signal whether or not a given picture was the same as the one they’d seen before. Using sophisticated measurement systems, the researchers then explored which cells in the cortex were dealing solely with remembering, and which with deciding the abstract issue of sameness vs. difference. To the group’s surprise, many more cells were dealing with the latter than the former. The work may mean that certain types of symptoms — in schizophrenics, for example, the short attention spans and difficulties making associations between two connected things — reflect abnormalities in thought processes, not memory deficits.
Planetary scientists have long speculated that a vast ocean may lie beneath a massive ice blanket on one of Jupiter’s moons. Recent research has provided tantalizing hints that liquid water exists on this body, called Europa, but hasn’t proven it. An MIT faculty member who has helped probe under the Arctic ice cap, though, says a technology used there could provide definitive answers. Nicholas Makris, professor of ocean engineering, has used small sonar devices in the Arctic work, and says adapted versions could be created that would dot Europa’s ice. Such a system could reveal if water lies below the frozen mantle, which is more than 60 miles deep in places. While Makris cautions that the completion of such a venture is at least 10 years off, confirming the existence of water on Europa could shed light on whether undersea life exists in that frigid corner of the solar system.
While humans debate what to do about global warming and urban air pollution risks, nature’s own atmospheric pollution-fighter is looking like a somewhat unpredictable partner in the struggle. This natural agent, called the hydroxyl radical, is made up of one atom each of hydrogen and oxygen — hence its chemical moniker, OH. The molecule breaks down many pollutants implicated in depletion of the ozone layer, smog formation and atmospheric warming. Problem is, levels of OH in the lower atmosphere seem to vary geographically and chronologically in unpredictable ways. According to Ronald Prinn, head of earth, atmospheric and planetary sciences at MIT and leader of an international research effort on OH, the molecule’s concentrations rose starting in 1978 but then decreased significantly from 1988 to 2000. In addition, it’s more concentrated in the southern than the northern hemisphere. The research group — whose results are based on years of global measurements of a gas, trichloroethane, that reacts with OH — can’t explain these variations, though they suspect human-generated pollutants may be partly to blame. In any case, says Prinn, the variations argue strongly for intensified efforts to understand this vital but mysterious denizen of the atmosphere.