25 December 2010/1 January 2011 | NewScientist | 13

New genes on the block prove vital

ARE your oldest genes your dearest? Geneticists thought that a creature’s vital genes are its oldest, not the new ones that constantly arise via mutation – after all, it got along fine without the newbies. This theory has now been proven wrong, in fruit flies at least.

Sidi Chen at the University of Chicago and colleagues found that about a third of fruit fly genes are vital, regardless of when they appeared. Surprisingly, the young genes found to be essential don’t deal with modern hazards such as pesticides, but the fly’s basic biology (Science, vol 330, p 1682).

The team created flies with a type of RNA that silenced certain genes. It either turned off one of 195 genes that arose in fruit flies less than 35 million years ago, or one of 245 genes from further back. In both groups, 30 per cent of flies died, with specific defects showing that the silenced genes controlled mainly early-stage development. Even very recent genes were vital.

The team describes new genes like go-getting new employees. They interact with existing genes to create some new function. If this is profitable and then selected for by evolution, the newcomer quickly becomes indispensable.

Dolls aren’t just for humans – wild chimps make their own WHEN Jane Goodall first reported that chimps use tools, our concept of human uniqueness was rocked. It has never quite recovered. In another twist, a population of wild chimps in Uganda’s Kibale National Park appears to be using objects as toys.

That’s remarkable in itself, but Sonya Kahlenberg of Bates College in Lewiston, Maine, and Richard Wrangham of Harvard University found that juvenile chimps in this population play with sticks like children play with dolls, cradling them and even making nests for

them to sleep in at night – and they found that the behaviour is more common in females.

“Stick carrying may be practice for the adult role of motherhood,” says Kahlenberg, “perhaps similar to functions of other kinds of play, being practice for adult roles.”

Kahlenberg and Wrangham analysed data from 14 years of observation of wild chimps and categorised stick-use into four classes: as probes to investigate holes; as weapons during aggressive displays or attacks; as a prop during solitary play; and,

ERUPTIONS on the sun’s surface may spark similar blasts across the star. The finding could help improve the forecasting of these eruptions, which disrupt power grids on Earth.

Solar eruptions are known to prompt further explosions nearby. But when two major eruptions, separated by hundreds of thousands of kilometres, both occurred on 1 August, Karel Schrijver and Alan Title of the Lockheed Martin Solar and Astrophysics Lab in Palo Alto, California, wondered whether they were connected.

The pair turned to detailed images

of the sun from August. Only a portion is visible at one time, but over a week, hidden areas became visible, revealing previously unknown distortions to the magnetic field. The researchers used these to estimate the magnetic field lines on 1 August over the sun’s entire surface and to map all solar events onto these lines.

This showed that the two major eruptions were linked to each other, and to other events, via the same deformations of the sun’s global magnetic field. The work will appear in the Journal of Geophysical Research.

Sun’s eruptions turn out to be global

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in essence, as dolls. This last class they call “stick carrying”, and in 301 observations it turned out to be more common in juvenile chimps, more frequent in females than males, and only occurred in females before their first birth (Current Biology, DOI: 10.1016/ j.cub.2010.11.024).

“It was striking that this behaviour was seen in some adult females, but never after they became mothers,” says Kahlenberg, adding that the chimps learned the behaviour by copying other juveniles.

Breast milk boosts schoolboys’ brains

BREASTFEEDING improves later academic performance in boys but appears to have no such effect in girls.

Wendy Oddy at the Telethon Institute for Child Health Research in Subiaco, Western Australia, and colleagues examined whether having been breastfed affected the test scores of over 1000 10-year-olds.

Studies have suggested that children who were breastfed have higher IQs than those who were not, but few separated out boys and girls. Mothers who breastfeed are on average wealthier and more educated, so Oddy’s team accounted for these factors.

Boys who were mainly breastfed for at least six months scored 9 per cent higher in mathematics and writing tests, 7 per cent higher in spelling, and 6 per cent higher in reading, compared with boys fed with formula milk or breastfed for shorter periods. There were no significant differences in results for girls (Pediatrics, DOI: 10.1542/peds.2009-3489).

“We know that breast milk contains the optimal nutrients for development of the brain and central nervous system,” says Oddy, but the gender differences were surprising.

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