In 1997, scientists found the first scrap of Neanderthal DNA in a fossil. Since then, they have recovered genetic material, even entire genomes, from a number of Neanderthal bones, and their investigations have yielded a remarkable surprise: Today, 1 to 2 percent of the DNA in non-African people comes from Neanderthals.

That genetic legacy is the result of interbreeding roughly 50,000 years ago between Neanderthals and the common ancestors of Europeans and Asians. Recent studies suggest that Neanderthal genes even influence human health today, contributing to conditions from allergies to depression.

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Many of our primate ancestors probably ended up in the bellies of big cats. How else to explain bite marks on the bones of ancient hominins, the apparent gnawing of leopards or other African felines?

Big cats still pose a threat to primates. In one study of chimpanzees in Ivory Coast, for example, scientists estimated that each chimp ran a 30 percent risk of being attacked by a leopard every year.

A new study suggests that the big cats may be getting some tiny help on the hunt. A parasite infecting the brains of some primates, including perhaps our forebears, may make them less wary.

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The Zika virus has quickly gained Ebola-level notoriety as it has spread through the Western Hemisphere in recent months. Researchers in Brazil, where it was first detected in May, have linked infections in pregnant women to a condition known as microcephaly: infants born with undersize heads.

Where birth defects are concerned, however, the Zika virus is far from unique. A number of other viruses, such as rubella and cytomegalovirus, pose a serious risk during pregnancy. Researchers have uncovered some important clues about how those pathogens injure fetuses — findings that are now helping to guide research into the potential link between Zika and microcephaly.

Continue reading “Scientists Investigate How Viruses Like Zika Cause Birth Defects” →