1. DNA UNIT 4

2. The doorbell rings. Busy in the kitchen fixing dinner, Nancy's dad calls out, "Answer the door, Nancy! My hands are full!" Nancy opens the front door, and suddenly a bunch of people she hasn't seen in 3 years pour into the house. Aunt Rita hands Nancy a wrapped package and says, "Well, look at you! How you've grown. And you've got such beautiful red, curly hair! It runs in the family, you know. You look just like my grandmother!" Uncle Michael adds, "And she's going to be tall, like her father. Only 9 years old, and she looks like a basketball player already!" Nancy makes a dash to the kitchen, wondering, "Huh? Aunt Rita's grandmother? Runs in the family? Basketball? What are they talking about?"

3. Genes (say: jeenz), that's what they're talking about. Genes are the things that determine physical traits - how we look - and lots of other stuff about us. They carry information that helps make you who you are: curly or straight hair, long or short legs, even how you might smile or laugh, are all passed through generations of your family in genes.