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Introns Nonsense DNA may be More Important to Evolution of Genomes than Thought


ScienceDaily
Mon, 14 Dec 2009 06:00 UTC
Image
© Robert Sommer
Daphnia pulex is a model organism for genetics study. Its genome was examined for recent intron colonization and loss events.
The sequences of nonsense DNA that interrupt genes could be far more important to the evolution of genomes than previously thought, according to a recent Science report by Indiana University Bloomington and University of New Hampshire biologists.

Their study of the model organism Daphnia pulex (water flea) is the first to demonstrate the colonization of a single lineage by "introns," as the interrupting sequences are known. The scientists say introns are inserted into the genome far more frequently than current models predict. The scientists also found what appear to be "hot spots" for intron insertion -- areas of the genome where repeated insertions are more likely to occur. And surprisingly, the vast majority of intron DNA sequences the scientists examined were of unknown origin.

"The thinking has been that these insertion events are very rare because they always have bad effects," said postdoctoral fellow Abraham Tucker, a lead author of the Science paper.
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Compass

MESSENGER team releases first global map of mercury


PhysOrg
Tue, 15 Dec 2009 16:17 UTC
NASA's MESSENGER mission team and cartographic experts from the U. S. Geological Survey have created a critical tool for planning the first orbital observations of the planet Mercury - a global mosaic of the planet that will help scientists pinpoint craters, faults and other features for observation. The map was created from images taken during the MESSENGER spacecraft's three flybys of the planet and those of Mariner 10 in the 1970s. A presentation on the new global mosaic is being given today at the fall meeting of the American Geophysical Union in San Francisco.

Image
© Arizona State University
Global map of Mercury showing regions imaged by MESSENGER during three flybys. Each image block is a mosaic of multiple spacecraft images. Black areas indicate no coverage. The final mosaic portrays Mercury’s surface in an equirectangular projection at 500 meters/pixel, -180° to +180° positive east longitudes and +90° to -90° planetocentric latitudes centered at 0° longitude and latitude. Because of projection distortion, unimaged regions appear artificially enlarged.
The MESSENGER spacecraft completed its third and final flyby of Mercury on Sept. 29, concluding its reconnaissance of the innermost planet. The MESSENGER team has been busily preparing for the yearlong orbital phase of the mission, beginning in March 2011, and the near-global mosaic of Mercury from MESSENGER and Mariner 10 images is key to those plans.
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Sun

Big New Sunspot Emerges


Space Weather
Tue, 15 Dec 2009 15:28 UTC
New sunspot 1035 is growing rapidly and it is now seven times wider than Earth itself (movie). The magnetic polarity of the spot identifies it as a member of new Solar Cycle 24.

Image
© SOHO/MDI
New sunspot 1035 is growing rapidly. It is a member of new Solar Cycle 24.
Readers with solar telescopes, train your optics on the sun to witness sunspot genesis in action.
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Fish

Prussian Blue Salt Linked to Origin of Life


ScienceDaily
Tue, 15 Dec 2009 06:00 UTC
Image
© Nagem R
This is Prussian blue. This salt could cause substances essential for life.
A team of researchers from the Astrobiology Centre (INTA-CSIC) has shown that hydrogen cyanide, urea and other substances considered essential to the formation of the most basic biological molecules can be obtained from the salt Prussian blue. In order to carry out this study, published in the journal Chemistry & Biodiversity, the scientists recreated the chemical conditions of the early Earth.

"We have shown that when Prussian blue is dissolved in ammoniac solutions it produces hydrogen cyanide, a substance that could have played a fundamental role in the creation of the first bio-organic molecules, as well as other precursors to the origin of life, such as urea, dimethylhydantoin and lactic acid," Marta Ruiz Bermejo, lead author of the study and a researcher at the Astrobiology Centre (CSIC-INTA), said.

Urea is considered to be an important reagent in synthesising pyrimidines (the derivatives of which form part of the nucleic acids DNA and RNA), and it has been suggested that hydantoins could be the precursors of peptides and amino acids (the components of proteins), while lactic acid is also of biological interest because, along with malic acid, it can play a role in electron donor-recipient systems.
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Magnify

'Rock-Breathing' Bacteria Could Generate Electricity and Clean Up Oil Spills


ScienceDaily
Tue, 15 Dec 2009 00:00 UTC
Image
© University of East Anglia
A discovery by scientists at the University of East Anglia could contribute to the development of systems that use domestic or agricultural waste to generate clean electricity.
A discovery by scientists at the University of East Anglia (UEA) could contribute to the development of systems that use domestic or agricultural waste to generate clean electricity.

Recently published by the scientific journal, Proceedings of the National Academy of Sciences (PNAS), the researchers have demonstrated for the first time the mechanism by which some bacteria survive by 'breathing rocks'.

The findings could be applied to help in the development of new microbe-based technologies such as fuel cells, or 'bio-batteries', powered by animal or human waste, and agents to clean up areas polluted by oil or uranium.

"This is an exciting advance in our understanding of bacterial processes in the Earth's sub-surfaces," said Prof David Richardson, of UEA's School of Biological Sciences, who is leading the project.
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Sherlock

4,000-Year-Old-Year-Old Flowers Found at Bronze Age Dig


BBC News
Tue, 15 Dec 2009 02:57 UTC
Image
© University of Glasgow
Archaeologists are excited by the flowerhead discovery
For the first time ever there is proof that pre-historic people placed bunches of flowers in the grave when they buried their dead, experts have said.

Archaeologists have discovered a bunch of meadowsweet blossoms in a Bronze Age grave at Forteviot, south of Perth.

The find is reported in the journal British Archaeology, out this week.

Pollen found in earlier digs had been thought to have come from honey, or the alcoholic drink mead but this find may finally rule that theory out.

Dr Kenneth Brophy, from the University of Glasgow, said the flowers "don't look very much. Just about three or four millimetres across."
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Meteor

Absence of Evidence for a Meteorite Impact Event 13,000 Years Ago


ScienceDaily
Mon, 14 Dec 2009 21:46 UTC
Image
© iStockphoto/Frank Van Den Bergh
Greenland
An international team of scientists led by researchers at the University of Hawaii at Manoa has found no evidence supporting an extraterrestrial impact event at the onset of the Younger Dryas approximately 13,000 years ago.

The Younger Dryas is an abrupt cooling event in Earth's history. It coincided with the extinction of many large mammals including the woolly mammoth, the saber toothed jaguar and many sloths. This cooling period is generally considered to be the result of the complex global climate system, possibly spurred on by a reduction or slowdown of the thermohaline circulation in North America. This paradigm was challenged two years ago by a group of researchers that reported finding high iridium concentrations in terrestrial sediments dated during this time period, which led them to theorise that an impact event was instead the instigator of this climate shift.

A team led by François Paquay, a Doctoral graduate student in the Department of Geology and Geophysics at the University of Hawaii at Manoa (UHM) decided to also investigate this theory, to add more evidence to what they considered a conceptually appealing theory. However, not only were they unable to replicate the results found by the other researchers, but additional lines of evidence failed to support an impact theory for the onset of the Younger Dryas.
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Meteor

Kansas scientists probe mysterious possible comet strikes on Earth

Brendan M. Lynch
University of Kansas
Mon, 14 Dec 2009 20:25 UTC
An investigation by the University of Kansas' Adrian Melott and colleagues reveals a promising new method of detecting past comet strikes upon Earth and gauging their frequency

It's the stuff of a Hollywood disaster epic: A comet plunges from outer space into the Earth's atmosphere, splitting the sky with a devastating shock wave that flattens forests and shakes the countryside.

But this isn't a disaster movie plotline.

"Comet impacts might be much more frequent than we expect," said Adrian Melott, professor of physics and astronomy at the University of Kansas. "There's a lot of interest in the rate of impact events upon the Earth. We really don't know the rate very well because most craters end up being destroyed by erosion or the comets go into the ocean and we don't know that they're there. We really don't have a good handle on the rate of impacts on the Earth."
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Sun

Theorists propose a new way to shine -- and a new kind of star

Kevin Mayhood
Case Western Reserve University
Mon, 14 Dec 2009 20:22 UTC
Dying, for stars, has just gotten more complicated.

For some stellar objects, the final phase before or instead of collapsing into a black hole may be what a group of physicists is calling an electroweak star.

Glenn Starkman, a professor of physics at Case Western Reserve University, together with former graduate students and post-docs De-Chang Dai and Dejan Stojkovic, now at the State University of New York in Buffalo, and Arthur Lue, at MIT's Lincoln Lab, offer a description of the structure of an electroweak star in a paper submitted to Physical Review Letters and posted online at http://arxiv.org/abs/0912.0520.
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Sun

New planet discoveries suggest low-mass planets are common around nearby star

Tim Stephens
University of California - Santa Cruz
Mon, 14 Dec 2009 20:17 UTC
An international team of planet hunters has discovered as many as six low-mass planets around two nearby Sun-like stars, including two "super-Earths" with masses 5 and 7.5 times the mass of Earth. The researchers, led by Steven Vogt of the University of California, Santa Cruz, and Paul Butler of the Carnegie Institution of Washington, said the two "super-Earths" are the first ones found around Sun-like stars.

"These detections indicate that low-mass planets are quite common around nearby stars. The discovery of potentially habitable nearby worlds may be just a few years away," said Vogt, a professor of astronomy and astrophysics at UCSC.

The team found the new planet systems by combining data gathered at the W. M. Keck Observatory in Hawaii and the Anglo-Australian Telescope (AAT) in New South Wales, Australia. Two papers describing the new planets have been accepted for publication in the Astrophysical Journal.
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