Biology

Lemurs self-medicate by rubbing toxic millipedes over their bottoms

Genetics - ср, 2018-08-01 13:20
Red-fronted lemurs sometimes pick up a millipede, give it a chew to make it secrete toxins, then rub it on the skin around their anus - but why?
Категории: Biology

Earth Overshoot Day – what to make of this moment of reckoning?

Genetics - ср, 2018-08-01 12:30
Earth Overshoot Day is a hugely popular way to highlight our global environmental impact. Here are two views on it...
Категории: Biology

An Amazonian snake has two types of venom that kill different prey

Genetics - ср, 2018-08-01 02:01
The Amazon puffing snake has evolved to deliver two kinds of venom with one bite – one kills lizards and birds but doesn’t harm mammals, and the other does the opposite
Категории: Biology

Maternal care boosted by paternal imprinting in mammals

PLOS Biology (new articles) - вт, 2018-07-31 23:00

by H. D. J. Creeth, G. I. McNamara, S. J. Tunster, R. Boque-Sastre, B. Allen, L. Sumption, J. B. Eddy, A. R. Isles, R. M. John

In mammals, mothers are the primary caregiver, programmed, in part, by hormones produced during pregnancy. High-quality maternal care is essential for the survival and lifelong health of offspring. We previously showed that the paternally silenced imprinted gene pleckstrin homology-like domain family A member 2 (Phlda2) functions to negatively regulate a single lineage in the mouse placenta called the spongiotrophoblast, a major source of hormones in pregnancy. Consequently, the offspring’s Phlda2 gene dosage may influence the quality of care provided by the mother. Here, we show that wild-type (WT) female mice exposed to offspring with three different doses of the maternally expressed Phlda2 gene—two active alleles, one active allele (the extant state), and loss of function—show changes in the maternal hypothalamus and hippocampus during pregnancy, regions important for maternal-care behaviour. After birth, WT dams exposed in utero to offspring with the highest Phlda2 dose exhibit decreased nursing and grooming of pups and increased focus on nest building. Conversely, ‘paternalised’ dams, exposed to the lowest Phlda2 dose, showed increased nurturing of their pups, increased self-directed behaviour, and a decreased focus on nest building, behaviour that was robustly maintained in the absence of genetically modified pups. This work raises the intriguing possibility that imprinting of Phlda2 contributed to increased maternal care during the evolution of mammals.
Категории: Biology, Journals

Comparative genomics and the nature of placozoan species

PLOS Biology (new articles) - вт, 2018-07-31 23:00

by Michael Eitel, Warren R. Francis, Frédérique Varoqueaux, Jean Daraspe, Hans-Jürgen Osigus, Stefan Krebs, Sergio Vargas, Helmut Blum, Gray A. Williams, Bernd Schierwater, Gert Wörheide

Placozoans are a phylum of nonbilaterian marine animals currently represented by a single described species, Trichoplax adhaerens, Schulze 1883. Placozoans arguably show the simplest animal morphology, which is identical among isolates collected worldwide, despite an apparently sizeable genetic diversity within the phylum. Here, we use a comparative genomics approach for a deeper appreciation of the structure and causes of the deeply diverging lineages in the Placozoa. We generated a high-quality draft genome of the genetic lineage H13 isolated from Hong Kong and compared it to the distantly related T. adhaerens. We uncovered substantial structural differences between the two genomes that point to a deep genomic separation and provide support that adaptation by gene duplication is likely a crucial mechanism in placozoan speciation. We further provide genetic evidence for reproductively isolated species and suggest a genus-level difference of H13 to T. adhaerens, justifying the designation of H13 as a new species, Hoilungia hongkongensis nov. gen., nov. spec., now the second described placozoan species and the first in a new genus. Our multilevel comparative genomics approach is, therefore, likely to prove valuable for species distinctions in other cryptic microscopic animal groups that lack diagnostic morphological characters, such as some nematodes, copepods, rotifers, or mites.
Категории: Biology, Journals

NASA’s plans to end the ISS could put its Mars missions in danger

Genetics - вт, 2018-07-31 18:33
A report on NASA's plans to stop funding the International Space Station by 2024 reveals that crucial studies on human spaceflight won't be done in time
Категории: Biology

Boy’s brain works just fine after a large piece was removed

Genetics - вт, 2018-07-31 18:00
A boy had a third of his right brain hemisphere removed to treat his epilepsy. His brain has now rearranged itself, preventing any cognitive impairment
Категории: Biology

When you ride the subway you share bacteria with everyone in your city

Genetics - вт, 2018-07-31 18:00
Unique bacterial communities exist on most Hong Kong subway train lines in the morning, but these merge during the day, also spreading antibiotic resistance
Категории: Biology

Pulses of laser light could find murder victims in unmarked graves

Genetics - вт, 2018-07-31 15:22
Unmarked graves can be difficult and time-consuming to find, but scanning with pulses of laser light could help us pinpoint where the bodies are buried
Категории: Biology

Climate change made Europe’s heatwave twice as likely to happen

Genetics - вт, 2018-07-31 14:15
The current heatwave in northern Europe was made twice as likely by climate change, according to a preliminary analysis.
Категории: Biology

De novo assembly of a young <i>Drosophila</i> Y chromosome using single-molecule sequencing and chromatin conformation capture

PLOS Biology (new articles) - пн, 2018-07-30 23:00

by Shivani Mahajan, Kevin H.-C. Wei, Matthew J. Nalley, Lauren Gibilisco, Doris Bachtrog

While short-read sequencing technology has resulted in a sharp increase in the number of species with genome assemblies, these assemblies are typically highly fragmented. Repeats pose the largest challenge for reference genome assembly, and pericentromeric regions and the repeat-rich Y chromosome are typically ignored from sequencing projects. Here, we assemble the genome of Drosophila miranda using long reads for contig formation, chromatin interaction maps for scaffolding and short reads, and optical mapping and bacterial artificial chromosome (BAC) clone sequencing for consensus validation. Our assembly recovers entire chromosomes and contains large fractions of repetitive DNA, including about 41.5 Mb of pericentromeric and telomeric regions, and >100 Mb of the recently formed highly repetitive neo-Y chromosome. While Y chromosome evolution is typically characterized by global sequence loss and shrinkage, the neo-Y increased in size by almost 3-fold because of the accumulation of repetitive sequences. Our high-quality assembly allows us to reconstruct the chromosomal events that have led to the unusual sex chromosome karyotype in D. miranda, including the independent de novo formation of a pair of sex chromosomes at two distinct time points, or the reversion of a former Y chromosome to an autosome.
Категории: Biology, Journals

Women have more miscarriages than live births over their lifetime

Genetics - пн, 2018-07-30 19:24
A study that brings together many different findings concludes that miscarriages are even more common than we thought
Категории: Biology

Terraforming Mars might be impossible due to a lack of carbon dioxide

Genetics - пн, 2018-07-30 18:00
We need lots of carbon dioxide to make Mars habitable for Earth life – and it turns out there isn’t enough on the Red Planet
Категории: Biology

Where does space begin? Here’s why it’s closer than you think

Genetics - пн, 2018-07-30 17:20
The jump from Earth to space is often thought to happen 100 kilometres up, but it's time to think again and bring the boundary closer to home, says Jonathan McDowell
Категории: Biology

Mass graves found on Scottish islands may be ancient tsunami victims

Genetics - пн, 2018-07-30 15:26
A rare tsunami may have struck the islands of Shetland and Orkney off the UK’s north coast 5500 years ago, killing dozens of people who had to be hastily buried
Категории: Biology

Biodiversity: Why the extinction crisis isn’t as bad as you thought

Genetics - пн, 2018-07-30 13:20
Earth’s life isn’t just beautiful, it ensures human survival. No one denies we’re harming it, but there’s grounds for optimism – and ways to turn things around
Категории: Biology

Biodiversity may prove to be the defining issue of our age

Genetics - пн, 2018-07-30 12:00
It’s an error to think we’ve got bigger problems than extinction. We must take species loss seriously, or it will come back to haunt us
Категории: Biology

From Ancillary Justice to Saga, savour the best sci-fi writing

Genetics - вс, 2018-07-29 12:00
We are in a new golden age of science fiction writing. Time to kick back and enjoy some of New Scientist's favourite new(ish) novels
Категории: Biology

Clean up your act with a clock that knows when you last vacuumed

Genetics - вс, 2018-07-29 09:00
A Fitbit for your vacuum cleaner keeps track of when you last did the cleaning and lets you know when you’ve been slacking off
Категории: Biology

Don’t miss: Latest Ant-Man film, exoplanets and a mind-blowing podcast

Genetics - сб, 2018-07-28 16:00
Enjoy the latest film in the Ant-Man franchise, find out what exoplanets can teach us about Earth and listen to an array of scientific marvels
Категории: Biology