The Ediacara fossil Fractofusus andersoni from the ~565 million year old Mistaken Point Formation in Newfoundland, Canada, represents the earliest Ediacara assemblage, known as the Avalon assemblage. Scientists have known for some time that most major groups of complex animals appeared in the fossils record during the Cambrian Explosion, a seemingly rapid evolutionary event that occurred 542 million years ago. Now Virginia Tech paleontologists, using rigorous analytical methods, have identified another explosive evolutionary event that occurred about 33 million years earlier among macroscopic life forms unrelated to the Cambrian animals. They dubbed this earlier event the "Avalon Explosion."

Practice makes perfect — or at least that’s what we’re told as we struggle through endless rounds of multiplication tables, goal kicks and piano scales — and it seems, based on the personal experience of many, to be true. That’s why neuroscientists have been perplexed by data showing that at the level of individual synapses, or connections between neurons, increased, repetitive stimulation might actually reverse early gains in synaptic strength. Now, neuroscientists from Carnegie Mellon University and the Max Planck Institute have discovered the mechanism that resolves this apparent paradox. The findings are published in the Jan. 4 issue of Science.

Even small mistakes made by cells during protein production can have profound disease effects, but the processes cells use to correct mistakes have been challenging to decipher. Recent work by scientists at The Scripps Research Institute, however, has uncovered two surprising new methods for such editing.

Two simple changes in its outer envelope protein could render the AIDS virus vulnerable to attack by the immune system, according to research from Kenya and the Fred Hutchinson Cancer Research Center published in PLoS Medicine.

Dynamic networks of growing actin filaments are critical for many cellular processes, including cell migration, intracellular transport, and the recovery of proteins from the cell surface. In this week’s issue of the open-access journal PLoS Biology, researchers at Washington University in St. Louis shed light on how multiple proteins cooperate to regulate the assembly of such actin networks.

Bright light therapy can ease bipolar depression in some patients, according to a study published in the journal Bipolar Disorders. Researchers from the University of Pittsburgh School of Medicine’s Western Psychiatric Institute and Clinic studied nine women with bipolar disorder to examine the effects of light therapy in the morning or at midday on mood symptoms.

Researchers at Johns Hopkins and Ohio State University have found that the number of copies of a particular gene can affect the severity of colon cancer in a mouse model. Publishing in the Jan. 3 issue of Nature, the research team describes how trisomy 21, or Down syndrome in humans, can repress tumor growth.

Asteroid impacts or massive volcanic flows might have occurred around the time dinosaurs became extinct, but a new book argues that the mightiest creatures the world has ever known may have been brought down by a tiny, much less dramatic force – biting, disease-carrying insects.