A creature called Caveasphaera lived in China 609 million years ago, and it left behind fossils that resemble tiny grains of sand. But as innocuous as those fossils appear, they may speak volumes about our own evolutionary history.

Under a microscope, the fossils turn out to be clusters of hundreds or thousands of cells. Were they on their way to developing into adult bodies? On Wednesday, a team of researchers published a study on hundreds of new Caveasphaera fossils, using high-powered X-ray beams to create three-dimensional images of the cells. They argue that these remains are embryos of early animals or their close relatives.

Continue reading “Is This the First Fossil of an Embryo?” →

The New York Times, November 20, 2019

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There’s no image in biology more iconic than our chromosomes — all 23 pairs of DNA bundles arrayed in a genetic lineup. But in a surprising number of cases, this picture leaves out something very important.

In some cells, extra circles of DNA float alongside the regular chromosomes. Scientists first noticed this so-called extrachromosomal DNA five decades ago. But for years they weren’t exactly sure what to make of it.

New research is now focusing on those mysterious loops. They are surprisingly common in cancer cells and play a bigger role in many types of cancers than was previously recognized.

Continue reading “Scientists Are Just Beginning to Understand Mysterious DNA Circles Common in Cancer Cells” →

The New York Times, November 14, 2019

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If you’ve ever noticed a slimy film of algae on a rock, chances are you didn’t pay it much attention. But some of these overlooked species hold clues to one of the greatest mysteries of evolution, scientists have found: how plants arrived on land.

On Thursday, researchers published the genomes of two algae that are among the closest known living relatives of land plants. They already had some of the key genes that plants would need to thrive on dry land.

Intriguingly, the authors of the new study find that the forerunners of plants gained some of their ability to survive on land by grabbing genes from other species — specifically, from bacteria.

Continue reading “How Did Plants Conquer Land? These Humble Algae Hold Clues” →

The New York Times, November 6, 2019

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Humans have spread a contagious form of cancer around the world.

Researchers reported on Tuesday that the cancer, which invades mussels, has spread across the Equator. Originating in one species in the Northern Hemisphere, the cancer has established itself in another species in the Southern Hemisphere.

“There’s no natural explanation for how that happened without human help,” said Michael Metzger, a biologist at the Pacific Northwest Research Institute in Seattle and a co-author of the report, published in the journal eLife.

Continue reading “Humans Shipped an Awful Cargo Across the Seas: Cancer” →

The New York Times, October 24, 2019

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Evolutionary biologists retrace the history of life in all its wondrous forms. Some search for the origin of our species. Others hunt for the origin of birds.

On Thursday, a team of researchers reported an important new insight into the origin of zombies — in this case, ants zombified by a fungus.

Here’s how it works: Sometimes an ant, marching about its business outdoors, will step on a fungal spore. It sticks to the ant’s body and slips a fungal cell inside.

Continue reading “After This Fungus Turns Ants Into Zombies, Their Bodies Explode” →