Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain
the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in
Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles
and JavaScript.
The toxic butterfly Heliconius numata, found in forests across South America, mimics the wing patterns of several species of another family of toxic butterflies, Melinaea sp., in order to deter predators more effectively. This example of M�lerian mimicry is under the control of a classic supergene, a tight gene cluster usually inherited as a single unit. H. numata is particularly adept at mimicry, able to copy as many as seven different wing patterns. A study of the individual wing-pattern morphs in H. numata shows that different genomic rearrangements at the single supergene P locus tighten the genetic linkage between loci that are otherwise free to recombine in other closely related species. The resulting supergene acts as a simple switch that, once thrown, selects which one of a range of complex adaptive phenotypes the butterfly displays. The cover shows Heliconius numata (top) and Melinaea mneme, from French Guiana. Photo: Mathieu Chouteau.
Scientists around the world should protest efforts by the government of Turkey to erode academic autonomy. And the wider world should note the threat to democracy.
The week in science: Iran's first commercial nuclear plant starts producing electricity; US shelves plans for stricter air-quality standards, and a study reports on mental disorders in Europe.
Since the anthrax attacks in 2001, some $60 billion has been spent on biodefence in the United States. But the money has not bought quite what was hoped.
In ten years of operation, the unwieldy Department of Homeland Security and its science directorate have seriously underperformed, says Peter D. Zimmerman.
John Robinson directs the Centre for Interactive Research on Sustainability (CIRS), a hub for sustainability research that opens for business this month in an ultra-green building at the University of British Columbia (UBC) in Vancouver, Canada. Robinson explains the practical challenges involved in turning a campus into a 'living lab'.
New ultra-high-resolution images of the radio galaxy M87 show the origin of a jet very close to the galaxy's black hole, revealing that jets start as broad flows before straightening into nearly cylindrical beams. See Letter p.185
Circuit-level perturbations in the brain's electrical activity may underlie social-interaction deficits seen in people with schizophrenia and autism. A new optogenetic tool was instrumental in making this discovery. See Article p.171
A specialist neuron uses an intriguing process to help control the body's response to hunger. A lipid pathway involving the breakdown of cellular components regulates the expression of a neuropeptide that affects feeding and body weight.
A 'late veneer' of meteoritic material, added after Earth's core had formed, may be the source of our noble metals. Its absence from some parts of Earth's mantle will now force a rethink about this late accretion. See Letter p.195
In hereditary breast and ovarian cancers caused by absence of the BRCA1 protein, genomic instability may ensue from the 'awakening' of repetitive DNA sequences in structurally condensed chromosomal regions. See Article p.179