Friday 5: Boy/girl brains, junk DNA coming in handy, and more

September 11, 2009

Brain differences between men and women aren’t necessarily hard-wired – finally, somebody making sense on this subject. A team at the U of Iowa found that the Straight Gyrus (SG) of the brain is larger in women and seems to correlate with interpersonal skills. But! They also compared SG size to a test of gender, in the personality sense – are you very masculine or very feminine? – and found it correlated better with gender than with biological sex. They also found that the relationship was reversed in children – boys had the larger SG. So do women have naturally better social skills or is that a skill they develop over time, resulting in brain changes? For once, somebody isn’t willing to jump to a conclusion.

(The writer of this article, Lise Eliot, has written a book on how differences between boys’ and girls’ brains are shaped by culture: “Boys are not, in fact, ‘better at math’ but at certain kinds of spatial reasoning. Girls are not naturally more empathetic; they’re allowed to express their feelings. By appreciating how sex differences emerge—rather than assuming them to be fixed biological facts—we can help all children reach their fullest potential.”)

People 32,000 years ago may have spun flax into twine (this is the same stuff as the fabric linen). We don’t know what the threads were used for, but speculation is rampant – clothing to keep warm? Rope to tie sharp things to sticks and make weapons? Or, um, nothing? “It’s possible individual flax fibers blew into the ancient cave, got buried and then became twisted during microscopic analyses,” says Harvard archaeologist Irene Good, who isn’t impressed with these fibers but told Science News that people probably did make some kind of textiles around that era. Ancient pottery (around 26,000 years ago) sometimes includes imprints of nets and ropes.

Late Blight’s genome published – the fungus that is wiping out tomato crops across the Northeast US this year (and that caused the Irish potato famine way back when) may owe its success to highly variable effector genes buried in its “junk” DNA. (“Junk” DNA is never junk, people. We just don’t always know what it does.)

Brown spots in bananas glow blue in UV light. The color change, from degrading chlorophyll, probably attracts insects (lots of animals can see in UV) but is also interesting to scientists as a marker of cell death.

How long food keeps in the fridge – a chart from the new FoodSafety.Gov website. Marion Nestle says, “If we can’t have a single food agency, we can at least have a single food safety site. Now if Congress would just pass some decent food safety laws…”


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