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Biggest ever 3D map of the galaxy pinpoints 1.7 billion stars

HIV and AIDS - Wed, 2018-04-25 16:31
The Gaia satellite has been scouring the sky for years. Over 22 months, it has located billions of stars and thousands of galaxies. Here’s what it found

The origins of sexism: How men came to rule 12,000 years ago

Genetically modified organisms (GMO) - Wed, 2018-04-25 15:00
Human societies weren’t always male-dominated. The switch came when we became farmers – and that suggests ways to roll back towards a more equal system
Categories: Science and society

The origins of sexism: How men came to rule 12,000 years ago

Genetics - Wed, 2018-04-25 15:00
Human societies weren’t always male-dominated. The switch came when we became farmers – and that suggests ways to roll back towards a more equal system
Categories: Biology

Theorem of everything: The secret that links numbers and shapes

Genetically modified organisms (GMO) - Wed, 2018-04-25 14:00
For millennia mathematicians have struggled to unify arithmetic and geometry. Now one young genius could have brought them in sight of the ultimate prize
Categories: Science and society

Ancient Swedish massacre hints at chaos after the fall of Rome

Genetically modified organisms (GMO) - Wed, 2018-04-25 14:00
The inhabitants of Sandby borg in southern Sweden were violently killed 1500 years ago, just decades after the collapse of the Western Roman Empire
Categories: Science and society

Theorem of everything: The secret that links numbers and shapes

Genetics - Wed, 2018-04-25 14:00
For millennia mathematicians have struggled to unify arithmetic and geometry. Now one young genius could have brought them in sight of the ultimate prize
Categories: Biology

Ancient Swedish massacre hints at chaos after the fall of Rome

Genetics - Wed, 2018-04-25 14:00
The inhabitants of Sandby borg in southern Sweden were violently killed 1500 years ago, just decades after the collapse of the Western Roman Empire
Categories: Biology

Ancient Swedish massacre hints at chaos after the fall of Rome

HIV and AIDS - Wed, 2018-04-25 14:00
The inhabitants of Sandby borg in southern Sweden were violently killed 1500 years ago, just decades after the collapse of the Western Roman Empire

How an Amazonian people convey their entire language by drumbeat

Genetics - Wed, 2018-04-25 02:01
The Bora people can encode complex messages into drumbeats that mimic human speech, and even include a “ringtone” to announce the start of a message
Categories: Biology

How an Amazonian people convey their entire language by drumbeat

HIV and AIDS - Wed, 2018-04-25 02:01
The Bora people can encode complex messages into drumbeats that mimic human speech, and even include a “ringtone” to announce the start of a message

How an Amazonian people convey their entire language by drumbeat

Genetically modified organisms (GMO) - Wed, 2018-04-25 02:01
The Bora people can encode complex messages into drumbeats that mimic human speech, and even include a “ringtone” to announce the start of a message
Categories: Science and society

Full disclosure: Genome assembly is still hard

PLOS Biology (new articles) - Tue, 2018-04-24 23:00

by Stephen Richards

Two recent papers highlight the fascinating comparative genomics of anhydrobiosis, the ability to withstand complete desiccation, in bdelloid rotifers and tardigrades. However, both groups had to openly deal with the significant difficulties of generating and interpreting short-read draft assemblies—especially challenging in microscopic species with high sequence polymorphism. These exemplars demonstrate the need to go beyond single draft-quality reference genomes to high-quality multiple species comparative genomics if we are to fully capture the value of genomics.
Categories: Biology, Journals

Evolutionary novelty in gravity sensing through horizontal gene transfer and high-order protein assembly

PLOS Biology (new articles) - Tue, 2018-04-24 23:00

by Tu Anh Nguyen, Jamie Greig, Asif Khan, Cara Goh, Gregory Jedd

Horizontal gene transfer (HGT) can promote evolutionary adaptation by transforming a species’ relationship to the environment. In most well-understood cases of HGT, acquired and donor functions appear to remain closely related. Thus, the degree to which HGT can lead to evolutionary novelties remains unclear. Mucorales fungi sense gravity through the sedimentation of vacuolar protein crystals. Here, we identify the octahedral crystal matrix protein (OCTIN). Phylogenetic analysis strongly supports acquisition of octin by HGT from bacteria. A bacterial OCTIN forms high-order periplasmic oligomers, and inter-molecular disulphide bonds are formed by both fungal and bacterial OCTINs, suggesting that they share elements of a conserved assembly mechanism. However, estimated sedimentation velocities preclude a gravity-sensing function for the bacterial structures. Together, our data suggest that HGT from bacteria into the Mucorales allowed a dramatic increase in assembly scale and emergence of the gravity-sensing function. We conclude that HGT can lead to evolutionary novelties that emerge depending on the physiological and cellular context of protein assembly.
Categories: Biology, Journals

Comparative genomics of bdelloid rotifers: Insights from desiccating and nondesiccating species

PLOS Biology (new articles) - Tue, 2018-04-24 23:00

by Reuben W. Nowell, Pedro Almeida, Christopher G. Wilson, Thomas P. Smith, Diego Fontaneto, Alastair Crisp, Gos Micklem, Alan Tunnacliffe, Chiara Boschetti, Timothy G. Barraclough

Bdelloid rotifers are a class of microscopic invertebrates that have existed for millions of years apparently without sex or meiosis. They inhabit a variety of temporary and permanent freshwater habitats globally, and many species are remarkably tolerant of desiccation. Bdelloids offer an opportunity to better understand the evolution of sex and recombination, but previous work has emphasised desiccation as the cause of several unusual genomic features in this group. Here, we present high-quality whole-genome sequences of 3 bdelloid species: Rotaria macrura and R. magnacalcarata, which are both desiccation intolerant, and Adineta ricciae, which is desiccation tolerant. In combination with the published assembly of A. vaga, which is also desiccation tolerant, we apply a comparative genomics approach to evaluate the potential effects of desiccation tolerance and asexuality on genome evolution in bdelloids. We find that ancestral tetraploidy is conserved among all 4 bdelloid species, but homologous divergence in obligately aquatic Rotaria genomes is unexpectedly low. This finding is contrary to current models regarding the role of desiccation in shaping bdelloid genomes. In addition, we find that homologous regions in A. ricciae are largely collinear and do not form palindromic repeats as observed in the published A. vaga assembly. Consequently, several features interpreted as genomic evidence for long-term ameiotic evolution are not general to all bdelloid species, even within the same genus. Finally, we substantiate previous findings of high levels of horizontally transferred nonmetazoan genes in both desiccating and nondesiccating bdelloid species and show that this unusual feature is not shared by other animal phyla, even those with desiccation-tolerant representatives. These comparisons call into question the proposed role of desiccation in mediating horizontal genetic transfer.
Categories: Biology, Journals

Agent-specific learning signals for self–other distinction during mentalising

PLOS Biology (new articles) - Tue, 2018-04-24 23:00

by Sam Ereira, Raymond J. Dolan, Zeb Kurth-Nelson

Humans have a remarkable ability to simulate the minds of others. How the brain distinguishes between mental states attributed to self and mental states attributed to someone else is unknown. Here, we investigated how fundamental neural learning signals are selectively attributed to different agents. Specifically, we asked whether learning signals are encoded in agent-specific neural patterns or whether a self–other distinction depends on encoding agent identity separately from this learning signal. To examine this, we tasked subjects to learn continuously 2 models of the same environment, such that one was selectively attributed to self and the other was selectively attributed to another agent. Combining computational modelling with magnetoencephalography (MEG) enabled us to track neural representations of prediction errors (PEs) and beliefs attributed to self, and of simulated PEs and beliefs attributed to another agent. We found that the representational pattern of a PE reliably predicts the identity of the agent to whom the signal is attributed, consistent with a neural self–other distinction implemented via agent-specific learning signals. Strikingly, subjects exhibiting a weaker neural self–other distinction also had a reduced behavioural capacity for self–other distinction and displayed more marked subclinical psychopathological traits. The neural self–other distinction was also modulated by social context, evidenced in a significantly reduced decoding of agent identity in a nonsocial control task. Thus, we show that self–other distinction is realised through an encoding of agent identity intrinsic to fundamental learning signals. The observation that the fidelity of this encoding predicts psychopathological traits is of interest as a potential neurocomputational psychiatric biomarker.
Categories: Biology, Journals

Activation of temperature-sensitive TRPV1-like receptors in ARC POMC neurons reduces food intake

PLOS Biology (new articles) - Tue, 2018-04-24 23:00

by Jae Hoon Jeong, Dong Kun Lee, Shun-Mei Liu, Streamson C. Chua Jr., Gary J. Schwartz, Young-Hwan Jo

Proopiomelanocortin (POMC) neurons in the arcuate nucleus of the hypothalamus (ARC) respond to numerous hormonal and neural signals, resulting in changes in food intake. Here, we demonstrate that ARC POMC neurons express capsaicin-sensitive transient receptor potential vanilloid 1 receptor (TRPV1)-like receptors. To show expression of TRPV1-like receptors in ARC POMC neurons, we use single-cell reverse transcription-polymerase chain reaction (RT-PCR), immunohistochemistry, electrophysiology, TRPV1 knock-out (KO), and TRPV1-Cre knock-in mice. A small elevation of temperature in the physiological range is enough to depolarize ARC POMC neurons. This depolarization is blocked by the TRPV1 receptor antagonist and by Trpv1 gene knockdown. Capsaicin-induced activation reduces food intake that is abolished by a melanocortin receptor antagonist. To selectively stimulate TRPV1-like receptor-expressing ARC POMC neurons in the ARC, we generate an adeno-associated virus serotype 5 (AAV5) carrying a Cre-dependent channelrhodopsin-2 (ChR2)–enhanced yellow fluorescent protein (eYFP) expression cassette under the control of the two neuronal POMC enhancers (nPEs). Optogenetic stimulation of TRPV1-like receptor-expressing POMC neurons decreases food intake. Hypothalamic temperature is rapidly elevated and reaches to approximately 39 °C during treadmill running. This elevation is associated with a reduction in food intake. Knockdown of the Trpv1 gene exclusively in ARC POMC neurons blocks the feeding inhibition produced by increased hypothalamic temperature. Taken together, our findings identify a melanocortinergic circuit that links acute elevations in hypothalamic temperature with acute reductions in food intake.
Categories: Biology, Journals

Stoner app lets cannabis users keep track of how high they are

Genetics - Tue, 2018-04-24 22:30
A series of smartphone tests that score memory and reaction are intended to make cannabis use safer and lead to a better understanding of the drug
Categories: Biology

Stoner app lets cannabis users keep track of how high they are

HIV and AIDS - Tue, 2018-04-24 22:30
A series of smartphone tests that score memory and reaction are intended to make cannabis use safer and lead to a better understanding of the drug

Stoner app lets cannabis users keep track of how high they are

Genetically modified organisms (GMO) - Tue, 2018-04-24 22:30
A series of smartphone tests that score memory and reaction are intended to make cannabis use safer and lead to a better understanding of the drug
Categories: Science and society

Gamma rays from the sun are acting weird and nobody knows why

Genetics - Tue, 2018-04-24 20:30
A survey of the sun’s radiation turned up two surprises: a dip in low-energy gamma rays, and far more high-energy gamma rays than predicted. And nobody knows why
Categories: Biology