A team of scientists unveiled a new tree of life on Monday, a diagram outlining the evolution of all living things. The researchers found that bacteria make up most of life’s branches. And they found that much of that diversity has been waiting in plain sight to be discovered, dwelling in river mud and meadow soils.

“It is a momentous discovery — an entire continent of life-forms,” said Eugene V. Koonin of the National Center for Biotechnology Information, who was not involved in the study.

The study was published in the journal Nature Microbiology.

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Five days a week, you can tune into “Paternity Court,” a television show featuring couples embroiled in disputes over fatherhood. It’s entertainment with a very old theme: Uncertainty over paternity goes back a long way in literature. Even Shakespeare and Chaucer cracked wise about cuckolds, who were often depicted wearing horns.

But in a number of recent studies, researchers have found that our obsession with cuckolded fathers is seriously overblown. A number of recent genetic studies challenge the notion that mistaken paternity is commonplace.

“It’s absolutely ridiculous,” said Maarten H.D. Larmuseau, a geneticist at the University of Leuven in Belgium who has led much of this new research.

Continue reading “Fathered by the Mailman? It’s Mostly an Urban Legend” →

The kakapo, a large flightless parrot that can live 95 years and perhaps longer, is dangerously close to extinction. Once found throughout New Zealand, the population has dwindled to fewer than 150.

Conservation biologists are doing everything they can to keep the kakapo from vanishing. And so, when they discovered a few years ago that a pair of captive kakapos were infected with tapeworms, they did the obvious thing: They dewormed the birds.

Hamish G. Spencer, a geneticist at the University of Otago in New Zealand, thinks that was unwise. If endangered species are going to escape extinction, he argues, they may need parasites to survive.

Continue reading “Tapeworms and Other Parasites Can Make Good Guests” →

It’s one of the most famous chapters in evolution, so familiar that it regularly inspires New Yorker cartoons: Some 375 million years ago, our ancestors emerged from the sea, evolving from swimming fish to vertebrates that walked on land.

Scientists still puzzle over exactly how the transition from sea to land took place. For the most part, they’ve had to rely on information gleaned from fossils of some of the intermediate species.

But now a team of researchers has found a remarkable parallel to one of evolution’s signature events. In a cave in Thailand, they’ve discovered that a blind fish walks the way land vertebrates do.

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The ancestors of modern humans interbred with Neanderthals and another extinct line of humans known as the Denisovans at least four times in the course of prehistory, according to an analysis of global genomes published Thursday in the journal Science.

The interbreeding may have given modern humans genes that bolstered immunity to pathogens, the authors concluded.

“This is yet another genetic nail in the coffin of our oversimplistic models of human evolution,” said Carles Lalueza-Fox, a research scientist at the Institute of Evolutionary Biology in Barcelona, Spain, who was not involved in the study.

Continue reading “Ancestors of Modern Humans Interbred With Extinct Hominins, Study Finds” →