iStockphoto

Sequencing the genes of a cancer cell turns up lots of genetic mutations — but some of them are harmless. The goal is to figure out which mutations are the troublemakers. Kevin Curtis/Science Source hide caption

itoggle caption Kevin Curtis/Science Source

After genetic testing revealed a heightened risk for breast cancer, Angelina Jolie had a precautionary double mastectomy. Alastair Grant/AP hide caption

itoggle caption Alastair Grant/AP

Each strand of DNA is written in a simple language composed of four letters: A, T, C and G. Your code is unique and could be used to find you. iStockphoto.com hide caption

itoggle caption iStockphoto.com

Should a high school student building a DNA model also have his genetic code tested for disease risks? iStockphoto.com hide caption

itoggle caption iStockphoto.com