21.   Experts think there are many causes but believe genes play a role.

22.   He said this indicates that these animals developed some sort of brain damage and suggests that the gene plays a role in protecting the brain from oxygen stress.

23.   If so, the gene may play some role in promoting obesity, he said.

24.   Past research has shown that genes play a major role in causing schizophrenia.

25.   Researchers said they were optimistic that the gene would play the same role in humans, but cautioned that it has been demonstrated only in mice so far.

26.   Researchers were skeptical because there had been no previous link between Apoe and the disease, but later research vindicated Roses by showing the gene does play a role.

27.   Such experiments will help determine whether the Id genes play a role in these situations, too.

28.   The gene MTHFR plays a role in how chromosomes separate during ovulation, and in how much folic acid people need for various bodily reactions.

29.   The gene plays a role in circuits in which brain cells communicate with squirts of a substance called dopamine.

30.   The GRPR gene plays a key role in the development of the lungs and the bronchial tree, but the gene is usually inactive in adults, Siegfried said.