Volume 520 Issue 7545

Editorials

Communication breakdown p.5

A policy change that could discourage UK government scientists from talking to the media is a backwards step. All researchers need to speak up to put science on the political agenda.

doi: 10.1038/520005a

Tree cheers p.5

The world must follow Brazil’s lead and do more to protect and restore forests.

doi: 10.1038/520005b

Walking 2.0 p.6

A passive device that augments calf muscles improves on natural selection’s best effort.

doi: 10.1038/520006a

News

News Features

Battle for the Amazon p.20

Brazil has waged a successful war on tropical deforestation, and other countries are trying to follow its lead. But victory remains fragile.

doi: 10.1038/520020a

Save blood, save lives p.24

Transfusions are one of the most overused treatments in modern medicine, at a cost of billions of dollars. Researchers are working out how to cut back.

doi: 10.1038/520024a

News & Views

Two-atom bunching p.36

The Hong–Ou–Mandel effect, whereby two identical quantum particles launched into the two input ports of a 'beam-splitter' always bunch together in the same output port, has now been demonstrated for helium-4 atoms. See Letter p.66

doi: 10.1038/520036a

A piece of the p53 puzzle p.37

An iron-dependent form of cell death called ferroptosis has been implicated as a component of the tumour-suppressor activity of p53, providing fresh insight into how this protein prevents cancer development. See Article p.57

doi: 10.1038/nature14374

Land use matters p.38

A meta-analysis at a local scale reveals that land-use change has caused species richness to decline by approximately 8.1% on average globally, mainly as a result of large increases in croplands and pastures. See Article p.45

doi: 10.1038/520038a

Preventing stars from eating their young p.40

Researchers have found a mechanism that prevents newly forming giant-planet cores from spiralling in towards their parent stars. The result may explain why planets such as Saturn and Jupiter are where they are today. See Letter p.63

doi: 10.1038/520040a

Coding in non-coding RNAs p.41

The discovery of peptides encoded by what were thought to be non-coding – or 'junk' – regions of precursors to microRNA sequences reveals a new layer of gene regulation. These sequences may not be junk, after all. See Letter p.90

doi: 10.1038/nature14378

Articles

Global effects of land use on local terrestrial biodiversity p.45

Analysis of a global data set of local biodiversity comparisons reveals an average 13.6% reduction in species richness and 10.7% reduction in abundance as a result of past human land use, and projections based on these data under a business-as-usual land-use scenario predict further substantial loss this century, unless strong mitigation efforts are undertaken to reverse the effects.

doi: 10.1038/nature14324

Loss of δ-catenin function in severe autism p.51

In severe autism, deleterious variants at conserved residues are enriched in patients arising from female-enriched multiplex families, enhancing the detection of key autism genes in modest numbers of cases.

doi: 10.1038/nature14186

Letters

Atomic Hong–Ou–Mandel experiment p.66

The Hong–Ou–Mandel effect—in which two indistinguishable photons that enter a 50:50 beam-splitter are found only as a pair at one of the two outputs, leading to a dip in the coincidence rate of the detectors—is now realized with 4He atoms instead of photons; this opens the way to performing basic quantum-physics experiments with mechanical observables of massive particles.

doi: 10.1038/nature14331

Primary transcripts of microRNAs encode regulatory peptides p.90

Plant primary microRNA (miRNA) transcripts (pri-miRNAs) are not just a source of miRNAs but can also encode regulatory peptides (miPEPs) that enhance the accumulation, and so the effect, of the corresponding mature miRNAs—an observation that may have agronomical applications.

doi: 10.1038/nature14346

G-protein-independent coupling of MC4R to Kir7.1 in hypothalamic neurons p.94

α-MSH and AgRP, two hypothalamus-derived peptides with opposing actions on the melanocortin-4 receptor (MC4R), modulate neurons driving feeding behaviour; although previous downstream mechanisms of cellular modulation by these peptides have been determined, here α-MSH and AgRP are shown to regulate neural activity by coupling MC4R to Kir7.1 potassium channels and closing or opening them, respectively.

doi: 10.1038/nature14051

Tel1ATM-mediated interference suppresses clustered meiotic double-strand-break formation p.114

Meiotic recombination is a critical step in gametogenesis for many organisms, enabling the creation of genetically diverse haploid gametes. In each meiotic cell, recombination is initiated by numerous DNA double-strand breaks (DSBs) created by Spo11, the evolutionarily conserved topoisomerase-like protein, but how these DSBs are distributed relatively uniformly across the four chromatids that make up each chromosome pair is poorly understood. Here we employ Saccharomyces cerevisiae to demonstrate distance-dependent DSB interference in cis (in which the occurrence of a DSB suppresses adjacent DSB formation)—a process that is mediated by the conserved DNA damage response kinase, Tel1ATM. The inhibitory function of Tel1 acts on a relatively local scale, while over large distances DSBs have a tendency to form independently of one another even in the presence of Tel1. Notably, over very short distances, loss of Tel1 activity causes DSBs to cluster within discrete zones of concerted DSB activity. Our observations support a hierarchical view of recombination initiation where Tel1ATM prevents clusters of DSBs, and further suppresses DSBs within the surrounding chromosomal region. Such collective negative regulation will help to ensure that recombination events are dispersed evenly and arranged optimally for genetic exchange and efficient chromosome segregation.

doi: 10.1038/nature13993