When scientists sequence tumor DNA, they typically find small amounts of genetic code from bacteria, viruses and fungi—microorganisms that—if actually present in tumor tissues—could influence how they ...

For nearly four billion years, life on Earth evolved blindly. Natural selection tinkered, mutations accumulated, and ...

For nearly four billion years, life on Earth evolved blindly. Natural selection tinkered, mutations accumulated, and organisms changed without foresight or design. Evolution, as scientists often say, ...