Video narration
If two children have the same parents, why don't they look exactly alike? Siblings often share family features. That resemblance comes partly from inherited DNA-the biological information passed from parents to children. But parents carry different versions of some DNA instructions, and each child receives a different combination. Same parents do not mean identical DNA. Those combinations can influence traits, including appearance and biological features. This difference is called variation: people can carry different versions of inherited information. But DNA is not a script for everything you notice. Traits are shaped by inherited DNA and other factors, such as the environment. Some DNA differences produce no visible or important change. So why can relatives resemble one another without being identical? Each child inherits a different mix of DNA versions, sharing enough family information to look related, while still having a combination of their own.