Planet Earth

Teens with fluctuating IQ, and worms that inherit a "memory of longevity"

Not Exactly Rocket ScienceBy Ed YongOct 19, 2011 11:33 PM

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This week, I'm filling in for one of the Guardian's science correspondents (the excellent Alok Jha), and I've been asked to cover a few stories that I would otherwise do here. So, let me direct you to the Guardian website where you'll find the two pieces I filed today. Worms can inherit a 'memory of longevity' from long-lived parents

Long-lived worms can transmit their extended lifespan to the next generation by passing on changes in the way their genes are used, rather than differences in DNA itself. A study has shown that nematode worms can inherit a "memory of longevity" from their parents, even though their genome remains unchanged. It is not clear if the same processes apply to humans, but Anne Brunet from Stanford University, who led the study, noted that some genes that affect the lifespan of nematodes were later found to influence human longevity too. "In several cases, the worm has proved to be a good model for humans, who live 2,000 times longer," she said. Her team is now looking to see if the results in the worm Caenorhabditis elegans translate to species that are evolutionarily closer to humans, such as fish and mice. The discovery is an example of "epigenetic inheritance", where organisms pass on changes in the way genes are used rather than in the genes themselves. As animals develop, their DNA and proteins become annotated by molecular marks that act like Post-It notes, dictating which genes are read without changing the underlying text. The marks are meant to be stripped away with each new generation, but some stay behind. [I'm glad the editors kept the bit at the end where I patiently explain why epigenetic inheritance isn't some sort of death knell for Darwinian evolution, and, in fact, fits snugly within it]

Teenagers' IQ scores can rise or fall sharply during adolescence

IQ scores can change dramatically in teenage years in parallel with changes to the brain, according to a study that suggests caution in using the 11+ exam for grammar school entrance to predict academic ability. IQ is thought to be stable across a person's life. Childhood scores are often used to predict education outcome and job prospects as an adult. But the study suggests scores are surprisingly variable. Robert Sternberg from Oklahoma State University, who studies intelligence but was not in the research team, said: "A testing industry has developed around the notion that IQ is relatively fixed and pretty well set in the early years of life. This study shows in a compelling way that meaningful changes can occur throughout the teenage years." Our mental faculties are not fixed, he said: "People who are mentally active and alert will likely benefit, and the couch potatoes who do not exercise themselves intellectually will pay a price." [Note: Redundant headline is redundant. I don't write 'em]

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