A gene is a unit of information that can be passed on to offspring. Genes help determine whether your hair is straight, whether your eyes are brown, and whether you can curl your tongue. They also may help determine whether you'll get a certain disease, have a learning disability, or be a gymnastics champion. Genes are powerful influences on physical and mental characteristics. Yet genes don't exist only in people.
Genes make hens white or speckled, give frogs smooth skin, and let roses smell sweet.
Genes are found in all living things. As mighty as genes are, however, it's important to remember that environment also helps shape organisms. A person might have a genetic predisposition to be tall, yet be short because of poor childhood diet. A plant might inherit a tendency to produce bright red blooms, but be unable to flower because of lack of nutrients. The interactions between a living thing and its environment affect how it will turn out.