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'Super' mouse evolves resistance to most poisons

Matt McGrath
British Broadcasting Corporation
Wed, 10 Aug 2011 16:05 UTC
Image
© Unknown
The mice acquired the trait through breeding with an Algerian species
Scientists say that some European house mice have developed resistance to the strongest poisons.

German and Spanish mice have rapidly evolved the trait by breeding with an Algerian species from which they have been separate for over a million years.

The researchers say this type of gene transfer is highly unusual and normally found in plants and bacteria.

The Current Biology report says this process could yield mice resistant to almost any form of pest control.

Warfarin is a drug widely used in medicine as an anti-coagulant to prevent the build-up of harmful blood clots. It works through inhibiting a protein called VKORC1. This protein turns on our ability to produce vitamin K, which is essential for clotting.

Too much warfarin can cause fatal bleeding, and it was this quality that led to its introduction as a pesticide against rats and mice in the 1950s.

But the creatures have been slowly evolving traits to survive warfarin, and pockets of resistant rodents have been found in many different parts of the world.
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Info

Why Do Women Have Twins?

Sara Reardon
Science Now
Tue, 09 Aug 2011 18:03 UTC
Twins
© U.K. Medical Research Council, Gambia Unit
Double trouble. Twins are an evolutionary disadvantage for themselves and their mothers, but their siblings might be better off in the long run.

Giving birth to twins is rough, especially in rural regions. They tend to be born smaller and weaker than single babies, and their mothers have more complications during childbirth. So why did twinning evolve? A new study in Gambia finds that women who have twins also tend to have single babies that are heavier than average at birth, which makes them more likely to survive.

Since the 1950s, the U.K. Medical Research Council has been collecting data and providing medical care in Gambia. It's a highly unusual data set, says evolutionary anthropologist Rebecca Sear of Durham University in the United Kingdom, with a length and thoroughness that's "unheard of for populations without good access to medical care." Evolutionary biologist Ian Rickard of the University of Sheffield in the United Kingdom wondered whether the data could shed light on the biology of twins.

Rickard and colleagues looked at the birth weights of 1889 single babies born to Gambian women over a 30-year period. Then they examined which of these mothers also had twins. Single babies born after twins were 226 grams heavier on average than single babies whose mothers had no twins, the team reports today in Biology Letters. This wasn't surprising, Rickard says, because carrying twins is thought to improve blood flow to the uterus and "prime" it for later children, allowing them to more easily receive nutrients. What did surprise the researchers was the discovery that when single babies were born before twins, the singles tended to be 134 grams heavier than average.
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Gene-Therapy Enzymes Make Unpredicted Errors

Heidi Ledford
Nature
Sun, 07 Aug 2011 15:39 UTC
Genes
© K. Eward / Science Photo Library
Zinc-finger nucleases can delete or swap genes by recognizing and cutting specific DNA sequences.

Molecular tools that alter specific sites in the genome hold huge promise for genetic research and gene therapy. But the first genome-wide surveys of where these tools, called zinc-finger nucleases, act has surprised researchers.

Two papers published today, one in Nature Biotechnology1 and one in Nature Methods,2 show that although zinc-finger nucleases are highly specific, the methods previously used to predict where they might go wrong miss the mark.

Zinc-finger nucleases are enzymes that can be designed to find specific DNA sequences in the genome and cut them out, deleting those sequences or swapping one gene for another. Clinical trials are underway in HIV patients of zinc-finger nucleases that remove a gene that allows the virus to enter immune cells.

The enzymes should be a vast improvement over conventional gene therapy, which uses viruses to insert genes into the genome almost at random. This unpredictability has caused problems: in one of the first clinical trials of gene therapy, five children treated for a rare immune disorder developed leukaemia because the viral vector embedded itself near cancer-causing genes.3

Zinc-finger nucleases are far more specific, but they still have the potential to make unwanted changes. "We need to know if they actually go where we think they will go," says David Segal, a molecular biologist at the University of California, Davis, who was not involved in the latest studies. "Nobody wants to have a zinc-finger nuclease loose in their cells that could make cancer-causing mutations."
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Info

Tiny Gene Changes Linked to Intelligence

Charles Q. Choi
Live Science
Tue, 09 Aug 2011 07:05 UTC
genes adn
© Desconocido

When it comes to smarts, which is more important - nature or nurture, genetics or environment? Well, yes, it seems. New findings now suggest that half of all differences in intelligence between people appear rooted in the collective influence of many tiny genetic variations. That leaves plenty of influence open to other factors, the researchers said.

Past research had suggested that bright parents tend to have bright kids. However, the extent to which genetics contributes to intelligence, as opposed to other contributing factors such as environment, has been hotly debated.

No single gene variant has yet been identified as reliably linked with intelligence. Instead, scientists investigated the potential role of many common genetic variations on human intelligence.

A gene is a string of molecules known as nucleotides, much as a word is a sequence of letters. The recipe of nucleotides making up each gene is not always precise - for instance, the copy of a gene a person has might differ by one nucleotide from the copy of that same gene seen in someone else, much as the word "cat" differs from "car" by a single letter.
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Magic Wand

Meteorites: Tool kits for creating life on Earth


Carnegie Institution
Mon, 08 Aug 2011 09:10 UTC
Image
© Unknown
Meteorites hold a record of the chemicals that existed in the early Solar System and that may have been a crucial source of the organic compounds that gave rise to life on Earth. Since the 1960s, scientists have been trying to find proof that nucleobases, the building blocks of our genetic material, came to Earth on meteorites. New research, published next week in the Proceedings of the National Academy of Sciences, indicates that certain nucleobases do reach the Earth from extraterrestrial sources, by way of certain meteorites, and in greater diversity and quantity than previously thought.

Extensive research has shown that amino acids, which string together to form proteins, exist in space and have arrived on our planet piggybacked on a type of organic-rich meteorite called carbonaceous chondrites. But it has been difficult to similarly prove that the nucleobases found on meteorite samples are not due to contamination from sources on Earth.

The research team, which included Jim Cleaves of Carnegie's Geophysical Laboratory, used advanced spectroscopy techniques to purify and analyze samples from 11 different carbonaceous chondrites and one ureilite, a very rare type of meteorite with a different type of chemical composition. This was the first time all but two of these meteorites had been examined for nucleobases.
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Info

A map of all the water in the solar system

Alasdair Wilkins
IO9
Thu, 04 Aug 2011 08:07 UTC
We've just learned that there's strong evidence that saltwater flows on the surface of Mars. It's another reminder that water is everywhere in our solar system, whether it's ice, vapor, or liquid. Here's a handy guide to where all the water can be found.

Our map is mainly focused on the places where we might find liquid water. There's a simple reason for that: Water molecules are incredibly bountiful throughout our solar system. Pretty much anywhere that there's an atmosphere, there's water vapor in it, and a huge percentage of the rocks in our solar system contain some amount of ice. So let's instead examine where conditions are just right for liquid water to exist.

Image
© Stephanie Fox
There's only one body in the solar system where we have indisputable evidence that there's liquid water on the surface - that, of course, would be Earth, although it now looks like Mars is the second, albeit on a much, much smaller scale. Going back billions of years, there's good evidence to think that Venus and Mars both supported large, Earth-like bodies of water, before changing climates made one too hot and the other too cold to support them any longer.
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Info

Astronomers Predict that Pluto Has a Ring


Technology Review, MIT
Mon, 08 Aug 2011 18:30 UTC
Pluto's Rings?
© Technology Review, MIT

Until recently, the only ring in the Solar System was Saturn's. But in 1960s and 70s, astronomers discovered rings around Uranus and Neptune. Meanwhile, the Voyager 1spacecraft sent back images of Jupiter's ring.

To be sure, these rings are much less impressive than Saturn's but the implications are clear: rings seem much more common than astronomers once thought. Perhaps they are even the norm.

And that raises an interesting question: could Pluto possibly have a ring?

The observational evidence is that Pluto does not have a ring. The best images are from the Hubble Space Telescope and they show nothing.

But today, Pryscilla Maria Pires dos Santos and pals at UNESP-São Paulo State University in Brazil say that Pluto ought to have a ring after all, but one that is too faint for Hubble to spot.

Their conclusion comes from modelling the way that micrometeorite impacts on Pluto's satellites, Nix and Hydra, ought to send dust into orbit about the dwarf planet.

This dust inevitably spirals into Pluto and its satellites because of its interaction with the solar wind. In this way, the dust is removed from orbit.

But that doesn't mean it can't form a ring. The important question is whether the dust can be replaced as quickly as it is removed.
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Info

Brain Finding May Explain Disoriented Pilots, Astronauts

Jennifer Welsh
Live Science
Mon, 08 Aug 2011 13:37 UTC
Brain Study
© NASA
NASA astronaut Andrew Feustel, STS-134 mission specialist, participates in the mission's firstspacewalk on May 20, 2011 as construction and maintenance continue on the International Space Station. A recent study, conducted on rats, may explain why pilots and astronauts often get disoriented. It suggests the brain's "map" of space is relatively flat; it's rich in detail on only one plane, the environment around us to the right and left, but it doesn't hold much information on up-and-down movement through space.
With every step you take, your brain is making a mental map of the environment. But new research suggests our mapmaking brain cells aren't good at encoding information on where a person is oriented within up-and-down space.

The study, conducted on rats, may explain why pilots and astronauts often get disoriented, suggests the brain's "map" of space is relatively flat; it's rich in detail on only one plane, the environment around us to the right and left, but it doesn't hold much information on up-and-down movement through space. (Rats are often used as a surrogate for brain-mechanism studies because their brains are very similar to ours, so the results likely apply to humans.)

"The implication is that our internal sense of space is actually rather flat - we are very sensitive to where we are in horizontal space but only vaguely aware of how high we are," study researcher Kate Jeffery, of University College London, said in a statement. "This finding is surprising, and it has implications for situations in which people have to move freely in all three dimensions - divers, pilots and astronauts for example.

In an email to LiveScience, Jeffery added: "It may at least partly explain the propensity for pilots, astronauts and divers to become easily disoriented in 3-D space. In pilots, this famously happens if they lose visual contact with the world (e.g. in thick cloud), but it is even more the case with astronauts, and to some extent deep-sea divers, where the usual cues to 'up' and 'down' become unavailable."
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Blackbox

Earth's Dirty Secret: Our Magnetic Field Traps Antimatter

Jason Mick
DailyTech Blog
Mon, 08 Aug 2011 17:46 UTC
Satellite confirms the existence of antimatter belts surrounding our planet, opens hopes for fuel use

Image
© VTM Physics Blog
Fifty-six years after their first laboratory observation, a treasure trove of antiprotons -- a component of antimatter (right) -- has been discovered within the Earth's magnetic field.
The proton is a familiar figure for those who have taken high school physics. With a +1 charge it is a key constituent to most of the matter of the universe. But nature holds an outlandish vanishing twin -- the antiproton. This exotic antimatter particle carries a -1 charge.

Now astrophysicists have discovered a treasure trove of antimatter hidden in the Earth's magnetic field, which could hold the key to grand insights and new space travel possibilities.
      Read More...
Gear

Bogus Science Claims: 'No Nemesis: Impact Events Not Periodic'

Ian O'Neill
Discovery News
Mon, 01 Aug 2011 13:50 UTC
Impact 1
© NASA/Earth Observatory
Tenoumer Crater, Mauritania

Trying to predict how much time we have before the next asteroid or comet impact event may sound like a fool's errand. After all, how can we forecast when a rare, yet devastating, space rock will careen through the inner solar system?

For starters, we could use statistics. Looking for patterns in a number of previous impact events is a valuable tool when trying to understand how often Earth was pummeled in the past. Once we know this, projections can be made for the risk of getting hit again.

However, according to a study by scientists of the Max Planck Institute for Astronomy (MPIA), the statistics we use to make these projections may be fundamentally flawed.


Comment: The premise that one can understand impact periodicity based on a statistical study of those visible craters left in the geological record is definitely a "fool's errand." This is not because impact periodicity isn't a real possibility, but because current science doesn't take into account all the possible ways that comet encounters occur.

The recent work of Dennis Cox shows that there are many more possible impact sites around the globe than currently supposed by mainstream geology. As Dennis is wont to say, "if you can describe a beast, you can predict its footprints." As we'll see below, it's clear that the scientists working on this study at the MPIA have not yet described the beast, let alone predicted its footprints.


Comment: Exactly, "from the crater record" (that being the key phrase) there is no evidence for a Nemesis body. Clearly, the crater record is not the only evidence we have that comet encounters occur on a cyclical basis.

Getting WISE About Nemesis

Nemesis: Does the Sun Have a 'Companion'?

Something Wicked This Way Comes

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