A nerve cell's long, slender tentacle isn’t evenly coated with an insulating sheath as scientists had thought.Instead, many nerve cells in the brains of mice have stretches of these tentacles, called axons, that are naked, researchers report April 18 in Science. The unsheathed feeler can be as long as 80 micrometers....
04/18/2014 - 18:00
News in Brief
Human cloning to produce stem cells works even with cells from middle-aged or elderly people, scientists report in the June 5 Cell Stem Cell, which appeared online April 17.Last year, scientists described a cloning technique for reprogramming human cells to make stem cells. That technique, known as somatic cell nuclear transfer,...
04/18/2014 - 15:32
In the newsroom, any story about a new scientific method faces an uphill battle. Editors are likely to reject such a story; writers themselves often downplay these stories because they’ve learned that the answer is usually “no.” To those of us who follow science, how scientists do what they do becomes important, and thus worth writing about, only once a new method reveals a novel truth about...
04/18/2014 - 15:30
Eating processed meat is associated with an increased risk of developing colon cancer in people who have the gene variant rs4143094, researchers report April 17 in PLOS Genetics. One in three people have this altered gene, which is found on the same...
04/18/2014 - 09:00
Exactly what molecule in a mammal's egg cell talks to sperm to let them wriggle inside has been difficult to identify. In 2005, scientists discovered that sperm carry a protein called Izumo1 that gets them to fuse with an egg. Now, research on mice shows that it's the protein folate receptor 4, or Folr4, on the egg that...
04/17/2014 - 20:00
Cells, Human Development
Extinct human cousins may have used some genes differently than modern people do, an analysis of Neandertal and Denisovan DNA reveals.Compared with living people, Neandertals and ancient Siberians known as Denisovans had slightly different patterns of DNA methylation — a chemical modification of DNA that doesn’t change the information in genes but helps control gene activity. Evolutionary...
04/17/2014 - 14:00
Genetics, Molecular Evolution, Human Evolution
When humans have a third copy of chromosome 21, they are usually diagnosed with Down’s syndrome. Scientists thought that the additional copy of the chromosome resulted in most of the traits characteristic of the condition. But the DNA of identical twins, one with Down’s and one without, suggests that there are genetic...
04/16/2014 - 18:20
Genetics, Human Development
Around 7,000 years ago, a bacterium that lives on humans and causes acne leaped to a very different host: domesticated grapevines. Since then, an essential DNA-repair gene in the microbe, Propionibacterium acnes, has mutated and no longer functions. Without the gene, the microbe is unable to function on its own and appears to rely on the grapevine for these DNA repairs. This is...
04/16/2014 - 15:30
Microbes, Genetics, Animals
Tanzania’s Hadza hunter-gatherers have guts teeming with bacteria much more diverse than what's found in Italians' intestines. But the foragers don't have Biﬁdobacterium, which is considered healthy, and do have more Treponema and other microbes that signal disease in Western populations. Hadza men and women even have major differences in their gut microbes.These differences...
04/15/2014 - 12:27
Cells have a relief valve that keeps them from swelling so much that they burst.For the past 30 years, scientists have been trying to pinpoint the molecule that controlled the valve. Now, a team says they have found the protein and gene, called SWELL1, which helps prevent cells from popping.The result, which appears April 10...
04/11/2014 - 14:43