A 3,000-year record from 52 of the world's oldest trees shows that California's western Sierra Nevada was droughty and often fiery from 800 to 1300, according to new research.

Previously unobservable events occurring between insemination and fertilization are the subject of a groundbreaking new article in Science magazine (March 18) by Mollie Manier, John Belote and Scott Pitnick, professors of biology in Syracuse University's College of Arts and Sciences. By genetically altering fruit flies so that the heads of their sperm were fluorescent green or red, Belote and his colleagues were able to observe in striking detail what happens to live sperm inside the female. The findings may have huge implications for the fields of reproductive biology, sexual selection and speciation.

Once the human genome was sequenced in 2001, the hunt was on for the genes that make each of us unique. But scientists at the European Molecular Biology Laboratory (EMBL) in Heidelberg, Germany, and Yale and Stanford Universities in the USA, have found that we differ from each other mainly because of differences not in our genes, but in how they're regulated – turned on or off, for instance. In a study published today in Science, they are the first to compare entire human genomes and determine which changes in the stretches of DNA that lie between genes make gene regulation vary from one person to the next. Their findings hail a new way of thinking about ourselves and our diseases.

A team of researchers at MIT and the University of California at San Diego has shown how cell division in a type of bacteria known as cyanobacteria is controlled by the same kind of circadian rhythms that govern human sleep patterns.

Patients seen at private facilities reimbursed by Medicare were more than 550 percent more likely to have routine cataract surgery than those who received their care from the Department of Veterans Affairs, a strong indication that the frequency of cataract surgery may be responsive to financial incentives to either or both the medical facility and the physicians who perform the procedure.

Urgent law enforcement action by governments in Central and West Africa and South-east Asia is crucial to addressing the illicit ivory trade, according to a new analysis of elephant trade data released today.

A team of Spanish researchers has studied the diet of three species of sharks living in the deep waters in the area of El Cachucho, the first Protected Marine Area in Spain, which is located in the Cantabrian Sea off the coast of Asturias. These animals feed on the resources available in their environment, according to changes taking place in the ocean depths.

Bees see the world almost five times faster than humans, according to new research from scientists at Queen Mary, University of London.

Dogs likely originated in the Middle East, not Asia or Europe, according to a new genetic analysis by an international team of scientists led by UCLA biologists. The research, funded by the National Science Foundation and the Searle Scholars Program, appears March 17 in the advance online edition of the journal Nature.

"Four and 20 black birds baked in a pie" – but wait, one has blue-gray eyes.

TAMPA, Fla. (March 16, 2010)—Bone marrow stem cells suspended in X-ray-visible microbubbles dramatically improve the body's ability to build new blood vessels in the upper leg—providing a potential future treatment for those with peripheral arterial disease or PAD, say researchers at the Society of Interventional Radiology's 35th Annual Scientific Meeting in Tampa, Fla.

A vaccine designed to prevent cervical cancer also may protect females from post-surgical recurrence of the disease, according to researchers at the University of Alabama at Birmingham (UAB).

It might sound like a mashup of monster movies, but palaeontologists have discovered evidence of how an extinct shark attacked its prey, reconstructing a killing that took place 4 million years ago.

What is causing the largest die-off of great whales ever recorded?