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Credit: Lake 578 in southern Greenland, where the research was conducted; photo by Raymond Bradley

One of the great mysteries of late medieval history is why the Norse, who established successful settlements in southern Greenland in 985, abandoned them in the early 15th century.

The consensus view has long been that the colder temperatures of the Little Ice Age helped make the colonies unsustainable. However, new research, led by scientists at the University of Massachusetts Amherst and published in Science Advances, upends that theory. It wasn't dropping temperatures that helped drive the Norse from Greenland, but drought. The research was supported by the U.S. National Science Foundation.

Credit: Hora Rockshelter in Malawi, where excavations uncovered individuals analyzed in an ancient DNA study; Jacob Davis

New research provides evidence of demographic shifts in sub-Saharan Africa

A new analysis of human remains buried in African archaeological sites has produced the earliest DNA from the continent, telling a fascinating tale of how early humans lived, traveled and even found their significant others.

An interdisciplinary team of 44 researchers outlined its findings in a paper published in Nature. The scientists report findings from ancient DNA from six individuals buried in Malawi, Tanzania and Zambia who lived between 18,000 and 5,000 years ago.

"This more than doubles the antiquity of reported ancient DNA data from sub-Saharan Africa," said David Reich of Harvard University, whose lab generated the data in the paper. "The study is particularly exciting as a collaboration of archaeologists and geneticists."

The study also reanalyzed published data from 28 individuals buried at sites across the continent, generating new data for 15 of them. The result was an unprecedented dataset of DNA from ancient African foragers -- people who hunted, gathered or fished. Their genetic legacy is difficult to reconstruct from present-day people because of the many population movements and mixtures that have occurred.

Section of a piling attacked by shipworms in Belfast, Maine. Credit: Barry Goodell

Researchers know less about the shipworm than previously thought

Humans have known for more than 2,000 years that shipworms, worm-like mollusks, are responsible for damage to wooden boats, docks, dikes and piers. Yet U.S. National Science Foundation-funded research from the University of Massachusetts Amherst, published in Frontiers in Microbiology, reveals that we don't know the most basic thing about them: how they eat.

"It's unbelievable," says Reuben Shipway, a microbiologist at UMass Amherst and one of the paper's authors. "The ancient Greeks wrote about them, Christopher Columbus lost his fleet due to what he called 'the havoc which the worm had wrought,' and, today, shipworms cause billions of dollars of damage a year."