Skip to main content
Premium Trial:

Request an Annual Quote

Gradually Becoming Big

Elephants don't grow so large overnight. And a new study published in PNAS shows that it takes at least 24 million generations for a mammal the size of a mouse to evolve into something as big as an elephant, reports Veronique Greenwood at Discover magazine's 80beats blog. "To get that number, researchers looked at the evolution of body mass over the last 70 million years, after the dinosaurs went extinct and surviving animals expanded into the ecological niches they left behind," Greenwood says. "That estimate is far longer than earlier estimates, which, extrapolating from bursts of super-fast evolution in mice, range from just 200,000 to 2 million generations."

The researchers also found that the opposite is true when the process is reversed. A large mammal grows smaller about 30 times faster than a small mammal getting larger does. This could reflect the fact that smaller organisms have an easier time finding resources and places to live than larger organisms, the researchers posit. "Certain physical constraints — the pull of gravity, for instance — might also make great size difficult to attain without unusual, physiologically expensive adaptations," Greenwood adds. "Tellingly, the rate of growth changes when you look at marine mammals, which are supported by the water around them. Body size can grow twice as fast in the water."

The Scan

Highly Similar

Researchers have uncovered bat viruses that are highly similar to SARS-CoV-2, according to Nature News.

Gain of Oversight

According to the Wall Street Journal, the Biden Administration is considering greater oversight of gain-of-function research.

Lasker for mRNA Vaccine Work

The Scientist reports that researchers whose work enabled the development of mRNA-based vaccines are among this year's Lasker Award winners

PLOS Papers on Causal Variant Mapping, Ancient Salmonella, ALK Fusion Test for NSCLC

In PLOS this week: MsCAVIAR approach to map causal variants, analysis of ancient Salmonella, and more.