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Virus gene engineer sends caterpillars to a sticky end
IN BRIEF
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IS THE glass half full or half empty? A gene variant usually considered to make people more gloomy could also help them see the positive. Previous studies have linked the short version of the 5-HTTLPR serotonin-transporter gene with vulnerability and depression, in contrast to the “happier” carriers of the long version. To explore further, Elaine Fox at the University of Essex in Colchester, UK, and colleagues asked 62 people with the short variant and 54 with the long version to perform computer exercises that tested how quickly they could identify a target superimposed either on a positive or negative image shown side by side. Unknown to the volunteers, in some exercises the team always flashed the target either on the positive or the negative image. People with the short variant adapted to this unconscious bias, identifying the target 40 to 60 milliseconds faster than when the target was randomly assigned. The reactions of long-variant volunteers barely changed (Biological Psychiatry, DOI: 10.1016/j.biopscych.2011.07.004). “The short version is not just a vulnerability variant,” says Fox. It could also be an “opportunity” gene, she says, suggesting that these people are more responsive to emotion, both positive and negative.
20 | NewScientist | 17 September 2011
Fathers are responsible for mother tongues YOUR mother tongue may come from your father. The language of some cultures correlates with a prehistoric influx of foreign males. This is still reflected in the genetics of people today. Written records are powerless to tell us about the evolution of language before writing was invented. Instead, Peter Forster and Colin Renfrew of the University of Cambridge wondered if changes could be traced via maternal or paternal genes, by studying mitochondrial DNA or Y-chromosome genes, respectively.
In a meta-analysis of studies that linked genetic markers to cultural heritage in North and Central America, Iceland, Australia, Africa and New Guinea, they found that only Y-chromosome DNA reflected the cultural origins of the local language. Iceland, for example, was colonised by Norse Vikings with women kidnapped from the British Isles. Most mitochondrial DNA found in Icelandic people today is similar to that in the British Isles, while Y chromosomes carry Scandinavian DNA. And the Icelandic language
has Scandinavian roots, not English (Science, DOI: 10.1126/ science.1205331). The finding suggests an interesting trend, but it is hard to identify a global pattern from this small selection of studies, says evolutionary anthropologist Keith Hunley of the University of New Mexico. Linguist Claire Bowern of Yale University, meanwhile, points out that the societies covered by this study distribute power through the male line, and the opposite correlation may be found in societies run by females. michael Grove
Half full or empty? Your genes decide
For new stories every day, visit newscientist.com/news
Buzz off, my place is better than yours HONEYBEES use the waggle dance to tell hive-mates about new nest sites – but they fine-tune the process with an anti-waggle song. When searching for another home, swarms set up camp in a tree and form a search committee of up to 500 scouts. The scouts tell others about potential sites by doing a waggle dance. The better the site, the longer each scout dances, and the more bees get recruited to that site. But there’s more to their powers of persuasion, says Tom Seeley of Cornell University in Ithaca, New York. By setting up good and bad nest sites, he found that scouts that favoured a particularly good site “beeped” other dancers, butting them and making high-pitched sounds. This made the other scouts dance less, and boosted the popularity of the preferred site, he explained at the summer conference of the Association for the Study of Animal Behaviour in St Andrews, UK, last month. The negative campaigning could help the colony make decisions faster, ensuring it is not homeless and exposed for long, says Lars Chittka of Queen Mary, University of London in the UK.
One gene to rule them all With that gene, a virus compels its caterpillar host to climb to a treetop, deliquesce and fall as a rosy rain of viral particles on healthy caterpillars below. Soon, they too will make the climb of doom. The virus is a baculovirus and its host the gypsy moth caterpillar. To find out how the baculovirus does it, and suspecting the involvement of a gene called egt, Kelli Hoover of Pennsylvania State University in University Park infected some caterpillars with virus that had egt and others with virus that did not. She placed them in bottles with food
at the bottom and a screen that they could climb to reach the top. Those whose virus contained egt died at the top of the bottles, in the manner typical of treetop disease, but the ones infected with the egt-less virus did nothing unusual (Science, DOI: 10.1126/science.1209199). Egt inactivates a moulting hormone that makes caterpillars hunker down and largely stop feeding on leaves. Hoover believes that by inactivating the hormone, the virus somehow controls the animals’ instinct to stay hidden, and coaxes them to their untimely death.
bildhaft/plainpicture
IS THE glass half full or half empty? A gene variant usually considered to make people more gloomy could also help them see the positive. Previous studies have linked the short version of the 5-HTTLPR serotonin-transporter gene with vulnerability and depression, in contrast to the “happier” carriers of the long version. To explore further, Elaine Fox at the University of Essex in Colchester, UK, and colleagues asked 62 people with the short variant and 54 with the long version to perform computer exercises that tested how quickly they could identify a target superimposed either on a positive or negative image shown side by side. Unknown to the volunteers, in some exercises the team always flashed the target either on the positive or the negative image. People with the short variant adapted to this unconscious bias, identifying the target 40 to 60 milliseconds faster than when the target was randomly assigned. The reactions of long-variant volunteers barely changed (Biological Psychiatry, DOI: 10.1016/j.biopscych.2011.07.004). “The short version is not just a vulnerability variant,” says Fox. It could also be an “opportunity” gene, she says, suggesting that these people are more responsive to emotion, both positive and negative.
20 | NewScientist | 17 September 2011
Fathers are responsible for mother tongues YOUR mother tongue may come from your father. The language of some cultures correlates with a prehistoric influx of foreign males. This is still reflected in the genetics of people today. Written records are powerless to tell us about the evolution of language before writing was invented. Instead, Peter Forster and Colin Renfrew of the University of Cambridge wondered if changes could be traced via maternal or paternal genes, by studying mitochondrial DNA or Y-chromosome genes, respectively.
In a meta-analysis of studies that linked genetic markers to cultural heritage in North and Central America, Iceland, Australia, Africa and New Guinea, they found that only Y-chromosome DNA reflected the cultural origins of the local language. Iceland, for example, was colonised by Norse Vikings with women kidnapped from the British Isles. Most mitochondrial DNA found in Icelandic people today is similar to that in the British Isles, while Y chromosomes carry Scandinavian DNA. And the Icelandic language
has Scandinavian roots, not English (Science, DOI: 10.1126/ science.1205331). The finding suggests an interesting trend, but it is hard to identify a global pattern from this small selection of studies, says evolutionary anthropologist Keith Hunley of the University of New Mexico. Linguist Claire Bowern of Yale University, meanwhile, points out that the societies covered by this study distribute power through the male line, and the opposite correlation may be found in societies run by females. michael Grove
Half full or empty? Your genes decide
For new stories every day, visit newscientist.com/news
Buzz off, my place is better than yours HONEYBEES use the waggle dance to tell hive-mates about new nest sites – but they fine-tune the process with an anti-waggle song. When searching for another home, swarms set up camp in a tree and form a search committee of up to 500 scouts. The scouts tell others about potential sites by doing a waggle dance. The better the site, the longer each scout dances, and the more bees get recruited to that site. But there’s more to their powers of persuasion, says Tom Seeley of Cornell University in Ithaca, New York. By setting up good and bad nest sites, he found that scouts that favoured a particularly good site “beeped” other dancers, butting them and making high-pitched sounds. This made the other scouts dance less, and boosted the popularity of the preferred site, he explained at the summer conference of the Association for the Study of Animal Behaviour in St Andrews, UK, last month. The negative campaigning could help the colony make decisions faster, ensuring it is not homeless and exposed for long, says Lars Chittka of Queen Mary, University of London in the UK.
One gene to rule them all With that gene, a virus compels its caterpillar host to climb to a treetop, deliquesce and fall as a rosy rain of viral particles on healthy caterpillars below. Soon, they too will make the climb of doom. The virus is a baculovirus and its host the gypsy moth caterpillar. To find out how the baculovirus does it, and suspecting the involvement of a gene called egt, Kelli Hoover of Pennsylvania State University in University Park infected some caterpillars with virus that had egt and others with virus that did not. She placed them in bottles with food
at the bottom and a screen that they could climb to reach the top. Those whose virus contained egt died at the top of the bottles, in the manner typical of treetop disease, but the ones infected with the egt-less virus did nothing unusual (Science, DOI: 10.1126/science.1209199). Egt inactivates a moulting hormone that makes caterpillars hunker down and largely stop feeding on leaves. Hoover believes that by inactivating the hormone, the virus somehow controls the animals’ instinct to stay hidden, and coaxes them to their untimely death.