Science: theoretically ...

Ice on Europa/ Animal organ transplants/ Intelligent offspring/ Smelling things

While everyone was getting excited about water on Earth's Moon, another Nasa spacecraft was finding good evidence folr slushy ice on another moon - Jupiter's Europa. Focussing on a crater 26 kilometres wide and 600 metres high, the Galileo mission found that its base seemed to be shallow, and at the same height as the surrounding terrain. That would imply that the crater's shape was altered by slushy ice - reckoned to lie underneath the hard ice cap - after the crater formed. Many scientists are increasingly convinced that Europa harbours an ocean beneath its ice cap: this is more evidence on their side.

More debate on whether it's wise to proceed with "xenotransplantion" - the use of genetically-engineered animal organs in humans. This time the argument is in the letters column of the science journal Nature. The US Public Health Service has rejected calls for a moratorium on such transplants (which has been imposed in the UK) over fears that retroviruses from the DNA of the donor animals could infect the recipients. "The risk would be justified only if large numbers of patients could be saved in the very near future and we had no hope of improving our risk assessment capabilities quickly. This is not the case..." says a writer from Oman. To which the American Society of Transplant Physicians and the American Society of Transplant Surgeons responds "it is time to proceed cautiously with well-defined and highly controlled clinical trials."

Better wombs make smarter children, according to research by a team at the University of Connecticut. Genetically identical mouse embryos implanted in different mothers performed differently at mental tasks - the first time the uterus has been shown to have a definite role in the cognitive ability of the offspring. The work is reported in the journal Neuroreport.

We don't smell as good as we used to. That is, many of the genes that help produce olfactory receptors have mutated so far that they aren't useful anymore, according to scientists at the Research Centre for Macromolecular Biochemistry in Montpellier, France. Previously it was reckoned that about 1,000 different receptors, most with large parts of identical DNA, mediate our sense of smell. But the Montpellier team anaylsed those genes and found that 72 per cent have mutated in a way that prevents them functioning. Their report in Nature Genetics suggests that our forebears had a much better sense of smell than we did.