Group of people % people with lactose intolerance

Americans of European descent

12%

African Americans

75%

Native Americans 100%Mexican Americans

55%

English 10%Greeks 50%Asian Americans 95%

Most people in the world…most mammals in the world…

stop making this protein after they are weaned.

Why?

JasonMom Tricia

Why does Jason have none of this protein?

Why do Mom and Tricia have less lactase?

Gel electrophoresis:Lactase samples from 4 people

JoelNumber of amino acids Origin 3500 3000

2500

2000

1500

1000

500

0