Random Samples

Science  27 Feb 2009:
Vol. 323, Issue 5918, pp. 1151


    Did prehistoric lasses make passes at lads with hand axes? In 1999, scholars proposed that the tear-drop shaped, often beautifully symmetrical axes produced by early humans were more than just tools. Rather, suggested Steven Mithen of the University of Reading in the United Kingdom and science writer Marek Kohn in a paper in the journal Antiquity, the best hand axes were the product of Darwinian sexual selection: a signal to gals that their makers had good, or at least handy, genes.

    Now, two anthropologists writing online this month in PaleoAnthropology argue against sexual selection. April Nowell of the University of Victoria in Canada and Melanie Lee Chang of the University of Oregon, Eugene, call the hypothesis “evocative and romantic.” But they say that the evidence for it doesn't hold up: For example, Mithen and Kohn argued that the axes' symmetry did not make them better tools, but Nowell and Chang cite several studies concluding that symmetry made the tools easier to control. The women also suggest that even early human females would have been seeking qualities in their mates—such as “niceness” and compatibility—more lasting than a well-turned hand ax. Kohn insists that he and Mithen aren't suggesting that female choice was “frivolous or superficial” but was based on how males performed difficult tasks.


    Sung-Hou Kim, a chemist at the University of California, Berkeley, usually explores gene and protein relationships. Now, Kim and colleagues are using similar algorithms to probe literary ties.

    Books, genes, and proteins can all be represented as strings of letters, which Kim's software analyzes to tease out underlying patterns. It's filed the Koran with other religious texts rather than with philosophical tracts as other literary comparison programs often do. Recently, the team cast fresh doubt on whether Shakespeare penned Pericles, Prince of Tyre, in which some scholars have detected the Bard's hand.

    Unlike programs that simply compare word frequencies, Kim's approach first strips the text of punctuation and spaces, transforming the book into a single string of letters. Their algorithm records the first eight letters in a string and then advances this “window” one letter and repeats. It then looks at the frequency with which two letters appear next to one another. “I'm just stunned” at how well it works, says Kim, who thinks that's because the eight-letter windows often span multiple words, thereby picking up common syntax patterns.

    The team has also found that the software can classify evolutionary relationships among hundreds of viruses, a feat that conventional tools struggle with because viruses share so few genes in common. Next, they hope to adapt the technique to analyze everything from musical patterns to ancient languages.


    Child abuse doesn't just cause emotional problems; scientists already know it can make for permanent changes in the brain. Now researchers in Canada have shown that a specific change seen in stressed baby rats can also be found in the brains of men who were abused as children.

    In rats, maternal neglect can permanently alter the workings of the hypothalamic-pituitary-adrenal (HPA) axis, a system that secretes particular hormones in response to stress. The regulatory region of a gene responsible for damping down the HPA axis response doesn't do the job, meaning the animals experience more stress throughout life.

    The same thing, it turns out, occurs in some human brains. Neuroscientist Michael Meaney and colleagues at McGill University in Montreal, Canada, compared methylation marks on relevant DNA from the brains of 12 men who had been abused as children and had later committed suicide with those of two other groups: age-matched suicides who had not been abused and nonabused men who had died suddenly from other causes. The abused men—but not the suicides who had not suffered child abuse—showed the same changes as the abused rats, the team reported online this week in Nature Neuroscience. Says Eric Nestler of Mount Sinai School of Medicine in New York City, “This is a beautiful study.”



    The Romans never conquered Iceland, but they left traces there: Lead particles from mining in Britain almost 2000 years ago blew all the way to sediments in this Icelandic salt marsh, report scientists in the United Kingdom. Geoscientist William Marshall of the University of Plymouth and colleagues say that lead in the marsh sediments near Vidarholmi on Iceland's west coast likely came from lead mines around Somerset, U.K.—about 1800 kilometers away—in the 1st and 2nd centuries C.E. The paper, in press in Science of the Total Environment, shows that even ancient human industrial activities had far-flung effects.

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