Genetics Spills Secrets From Neanderthals’ Lost History

In 1856, three years before the publication of Charles Darwin’s On the Origin of Species, a group of miners uncovered human fossils in a limestone cave in the Neander Valley of northern Germany — what would later be named Neanderthal 1, the first specimen to be recognized as belonging to another, archaic species of human. We have been trying to understand as much as possible about our mysterious cousins ever since. To do so, experts have consulted two major lines of evidence: the hundreds of bones and stone tools found to date, scattered from Spain and England to the Altai Mountains, and, much more recently, genomic data and inferences drawn from statistical models.

But these approaches paint strikingly different pictures of what Neanderthal populations would … Read the rest

Viruses Would Rather Jump to New Hosts Than Evolve With Them

When new species evolve, where do their viruses come from? As little more than free-ranging bundles of genetic material, viruses desperately need to hijack their hosts’ cellular machinery and resources to replicate, over and over again. Without its host, a virus is nothing.

Because of that dependence, some viruses have stuck with their hosts throughout evolution, mutating to make minor adjustments every time the host branched into a new species — a process called co-divergence. Humans and chimpanzees, for instance, have slightly different versions of the hepatitis B virus, both of which likely mutated from a version that infected their shared ancestor more than four million years ago.

The other option — cross-species transmission — occurs when a virus jumps into a completely new type of … Read the rest

Bacteria Use Brainlike Bursts of Electricity to Communicate

Bacteria have an unfortunate — and inaccurate — public image as isolated cells twiddling about on microscope slides. The more that scientists learn about bacteria, however, the more they see that this hermitlike reputation is deeply misleading, like trying to understand human behavior without referring to cities, laws or speech. “People were treating bacteria as … solitary organisms that live by themselves,” said Gürol Süel, a biophysicist at the University of California, San Diego. “In fact, most bacteria in nature appear to reside in very dense communities.”

The preferred form of community for bacteria seems to be the biofilm. On teeth, on pipes, on rocks and in the ocean, microbes glom together by the billions and build sticky organic superstructures around themselves. In these films, … Read the rest