1.   This discovery brings together two rapidly advancing fields by demonstrating that a tumour-suppressor gene plays an essential role in the induction of programmed cell death.

2.   Both genes play a role in fat accumulation.

3.   A complex condition like heart disease probably occurs when several genes play discordant notes, Fodor said.

4.   But what role do the genes play?

5.   Clearly, genes play a part.

6.   Early indications are that genes do play some role, although experts debate how important it is.

7.   Even the harshest critics do not deny that genes play some role in behaviors.

8.   Lewontin, an evolutionary geneticist, stresses that he is not denying the important role that genes play in human development.

9.   More challenging are diseases in which many genes play smaller roles.

10.   Now, scientists are seeking to discover how specific genes play a role in disease.