For someone 2.5 inches shorter than average, the risk of coronary artery disease increases by about 13.5 percent, scientists found. PW Illustration/Ikon Images/Corbis hide caption

itoggle caption PW Illustration/Ikon Images/Corbis

The H1N1 swine flu virus kills some people, while others don't get very sick at all. A genetic variation offers one clue. Centre For Infections/Health Pro/Science Photo Library/Getty Images hide caption

itoggle caption Centre For Infections/Health Pro/Science Photo Library/Getty Images

The size of the brain of a chimpanzee (right) is considerably smaller than that of a human brain. Probably multiple stretches of DNA help determine that, geneticists say. Science Photo Library/Corbis hide caption

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Daniel Horowitz for NPR

Researcher Svante Pääbo, was able to extract a complete genome from this ancient human leg bone. Bence Viola/Max Planck Institute for Evolutionary Anthropology hide caption

itoggle caption Bence Viola/Max Planck Institute for Evolutionary Anthropology

Jennifer Doudna and her colleagues found an enzyme in bacteria that makes editing DNA in animal cells much easier. Cailey Cotner/UC Berkeley hide caption

itoggle caption Cailey Cotner/UC Berkeley

A technician tests samples from Ebola-infected patients at a field lab, run by Doctors Without Borders, in Kailahun, Sierra Leone. Tommy Trenchard for NPR hide caption

itoggle caption Tommy Trenchard for NPR

The human Y chromosome (left) holds the code for "maleness"; that's the X on the right. Andrew Syred/Science Source hide caption

itoggle caption Andrew Syred/Science Source
Oivind Hovland/Ikon Images/Corbis

Being able to insert the two man-made letters into DNA, alongside the usual four-letter alphabet, could teach old cells new tricks and lead to better drugs, researchers say. courtesy of Synthorx hide caption

itoggle caption courtesy of Synthorx

Women make up nearly two-thirds of the people in the U.S. diagnosed with Alzheimer's disease. iStockphoto hide caption

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Mary-Claire King says obscurity gave her the freedom to spend years looking for breast cancer genes. Mary Levin/University of Washington hide caption

itoggle caption Mary Levin/University of Washington

The new test scans a mother's blood for bits of a fetus's DNA. iStockphoto hide caption

itoggle caption iStockphoto

Up till now, all babies have had two genetic parents. That could soon change. Klöpper & Eisenschmidt GbR/iStockphoto hide caption

itoggle caption Klöpper & Eisenschmidt GbR/iStockphoto

Research excavations like these in Siberia's Denisova Cave are yielding clues to the mating choices of early hominids. Bence Viola/Nature hide caption

itoggle caption Bence Viola/Nature

This micrograph shows a single mitochondrion (yellow), one of many little energy factories inside a cell. Keith R. Porter/Science Source hide caption

itoggle caption Keith R. Porter/Science Source