The Grandfather of Galaxies

Somewhere out —about 13.2 billion light-years away— the Hubble Space Telescope has recently discovered a magnificent red, amorphous mass. It's a galaxy —or it was— but it is not beautiful, it is magnificently old.

The newly discovered star block — a hundred times smaller than our Milky Way — was formed just 480 million years after the 13.7 billion-year-old universe was born, making it the oldest galaxy. As such, it provides astronomers with a look at the universe in a phase when small galaxies were being formed out of hot gas, only to disappear —leaving the skies free for the immense and mature galaxies that would come along later.

Its size, shape and the era in which it formed all suggest that it began its life as a mass of gas trapped in a pocket of dark matter. In those early days, stars took about 10 times as long to form as they did in later epochs. They were typically part of the blue star class — extremely hot stars, heavy on helium, oxygen and nitrogen. Blue stars last only a few million years before ending their lives in massive explosions.

Soon, stabler stars began to form in much larger galaxies as the universe rapidly cooled. Between 480 million and 700 million years after the Big Bang — when UDFj-39546284 was still in the skies — star formation accelerated. It was then when spiral galaxies and the other glorious formations that define the modern universe appeared.

It is not certain what forces drove those changes. The Hubble Space Telescope has a lot more work to do before more answers are revealed — and a lot more images of thousands of other galaxies to analyze.

By Jeffrey Kluger, TIME Magazine. Picture by NASA.

Health Philosphy

In his book The New Evolution Diet Arthur De Vany, who used to work as a professor at the University of California, argues if we really want to be healthy, we should follow Paleolithic humans' lifestyle. He thinks we should eat low-carb food and exercise intensely in order to control insulin.

De Vany has become the grandfather of the growing Paleo movement, a health philosophy. Their slogan could be reduced to “modern life is simply alien to our genes”. We should return to eat wild animals, fresh produce, eliminate grains and milk, and exercising in intense bursts.

There's no doubt that obesity, heart disease and diabetes are a big problem. And there's no doubt that this is a direct result of our sedentary lives. But there was no Paleolithic "lifestyle." Life in Ice Age Europe was different from life on the African savanna, requiring different diets, behaviors and genetic adaptations. Human DNA evolution didn't stop then. In fact, we're still evolving.

Human genetic adaptations actually increased around 40,000 years ago when we developed technology and became more sophisticated, cooperative thinkers. At least 3,000 significant genetic adaptations have occurred since, including the ability of some Africans, central Asians and northern Europeans to tolerate lactose as adults.

The problem, of course, is that even if De Vany and the other paleo believers are right, there's no going back to the world that existed 40,000 years ago. There's not enough wild animals to feed us all, and our genes don't care how healthy we are, but whether we reproduce or not. From an adaptation perspective, people today are doing really well: there are several billion of us.

From TIME Magazine, by Jennifer Pinkowski. Picture: North Wind Picture Archives / AP Images.

Pet Detective

Your pet already lowers your blood pressure and gives you emotional support. What if it could also identify your colon cancer?

In a new study, a Labrador learned how to sniff out cancer and was able to detect colon cancer. It was nearly as efficient as a colonoscopy. The dog was given breath samples of 306 patients, collected before they received colonoscopies; 48 patients had recently been diagnosed with cancer, and the other 258 were either suffering from another colorectal problem or had survived cancer, or were healthy.

The investigators found that the dog was at least 95% as competent at identifying cancer as colonoscopy when smelling breath samples. But the most important advantage of this technique is that the dog was especially good at detecting early-stage cancer, and could discern polyps from malignancies, which colonoscopies can't do. Detection of early-stage cancers is crucial in bowel cancer diagnosis because surgery can cure almost 90% of patients at an early stage.

Although we will not see the routine use of scent dogs in cancer screening (they're too expensive), this investigation suggests that other methods could be developed to pick up the same scent: a specific cancer smell exists and may become very effective tools.

From TIME Magazine, by Meredith Melnick. Picture by Juliet White/Photographer's Choice via Getty Images.

Mosquitoes and malaria

The discovery of a mosquito that spends most of its time outside could cause problems for malaria control.

In sub-Saharan Africa, malaria kills some 710,000 people each year. The most dangerous form of the disease is caused by a parasite, Plasmodium falciparum, which is transmitted by mosquitoes, mainly of the species Anopheles gambiae. The mosquito larvae live in water, but the adult insects spend much of their time in buildings, where they have human blood. Insecticide sprays, bed nets and access to malaria medication have helped to decrease the number of deaths from malaria.

The newly discovered mosquito group — a subtype of Anopheles gambiae, could be responsible for eradication not being successful. The insects spend their time outside, and then avoid insecticide.

For decades, everybody has thought that the mosquito rests indoors and bites people indoors but collection methods might be wrong. Collecting adult mosquitoes outside is notoriously difficult: traps with artificial bait are inefficient, and using human bait is banned. The aquatic larvae are easier to catch, and they reveal details such as the individual's place of birth. So some larvae were collected and raised to adulthood in the lab.

The scientists tested them for genetic markers and mutations, and compared them with adults caught inside. They found that the indoor insects consisted of two previously known types of Anopheles gambiae. But the outdoor mosquitoes had three distinct types — the two known ones and the previously unknown group. And 58% of new mosquitoes picked up the parasite that transmits malaria, compared with 35% of the indoor mosquitoes.

Extracted from an article by Amy Maxmen in Nature News. Picture by Kenneth Vernick.

Water fleas and toxicity testing

The genome of the water flea Daphnia pulex has been sequenced for the first time. Its DNA contains the largest number of genes ever recorded for a multicellular animal, and could help check the toxicity of chemicals or environmental pollutants without experiments on rats or mice.

Daphnia is a small crustacean found in water all over the world and an important food source for fish. The authors of a study have identified 30,907 genes in its genome; more than one-third of them are not seen in any other organism.

This study is relevant because scientists want to investigate toxins that could be dangerous to the environment or to human health. But until now, studies have been limited to traditional model organisms whose genomes have been sequenced, such as fruit fly (Dosophila melanogaster) or mouse (Mus musculus). This is not so good because the genes considered most important by ecological geneticists are difficult to find in traditional model organisms kept under controlled laboratory conditions. Daphnia, however, is an ecologically-relevant organism that, with the genome in hand, will allow scientists to test the environment.

Daphnia has unusual biology that could be used to get a lot of crucial information. For example, Daphnia eggs can lay dormant in sediments for hundreds of years, so scientists can trace past population-level adaptations to environmental stresses, such as metal toxicities from mining. The crustacean can also clone itself, so ecologists will be able to expose individual genetically identical water fleas to different environmental stressors and track changes in their gene expression.

Extracted from an article by Virginia Gewin in Nature News. Picture by Science/AAAS.