It was only two years ago that researchers found the first ancient human genome in Africa: a skeleton in a cave in Ethiopia yielded DNA that turned out to be 4,500 years old.

On Thursday, an international team of scientists reported that they had recovered far older genes from bone fragments in Malawi dating back 8,100 years. The researchers also retrieved DNA from 15 other ancient people in eastern and southern Africa, and compared the genes to those of living Africans.

Their analysis, published in the journal Cell, reveals important clues to Africa’s mysterious prehistory, including details of massive migrations that shaped the populations we know today.

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Animals around the world are on the move. So are their parasites.

Recently, scientists carried out the first large-scale study of what climate change may do to the world’s much-loathed parasites. The team came to a startling conclusion: as many as one in three parasite species may face extinction in the next century.

As global warming raises the planet’s temperature, the researchers found, many species will lose territory in which to survive. Some of their hosts will be lost, too.

Continue reading “Climate Change Threatens the World’s Parasites (That’s Not Good)” →

Climate change will dramatically alter life in the oceans, scientists say, but there’s so much still to learn about marine ecosystems that it’s hard to know exactly how.

On Thursday, researchers with the British Antarctic Survey offered a glimpse of that future with the results of an unusual study years in the making.

The scientists heated a patch of the sea floor off the coast of Antarctica and tracked the effects on a few local species. Some animals responded by doubling their growth, stunning the researchers.

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In Tanzania, not far from the Serengeti, live the Hadza, a community of about 1,300 people. For such a small group, they attract a lot of scientific attention.

Many of the Hadza live solely on the animals they kill, along with honey, berries and a few other wild foods. For the first 95 percent of our species’ history, there was no other way to live.

So the Hadza have been closely scrutinized for clues about the hunter-gatherer way of life: how they find their food, how much energy they use — even how much sleep they get.

Continue reading “Gut Bacteria Can Fluctuate With the Seasons” →

In a significant advance in the study of mental ability, a team of European and American scientists announced on Monday that they had identified 52 genes linked to intelligence in nearly 80,000 people.

These genes do not determine intelligence, however. Their combined influence is minuscule, the researchers said, suggesting that thousands more are likely to be involved and still await discovery. Just as important, intelligence is profoundly shaped by the environment.

Continue reading “In ‘Enormous Success,’ Scientists Tie 52 Genes to Human Intelligence” →