Walter Sutton was an American cytologist, or someone who studies cells. He studied the cells of grasshoppers because there was an abundance of grasshoppers in his area. He wanted to know how sex cells form. Sutton focused on the movement of chromosomes during the formation of sex cells. He was trying to figure out what happens to chromosomes when an organism creates sex cells. He figured that chromosomes were the key to understanding why offspring have similar features to those of their parents.