31.   This could be explained by defective leptin receptors in the brain, which would likely be controlled by a different gene.

32.   They repeated the procedure with different genes.

33.   Two people can have different gene sequences for the same receptor involved in pain control.

34.   A different gene was previously associated with aging in a type of worm.

35.   Gene therapy has come under harsh criticism since September, when a different gene therapy experiment killed an Arizona teen-ager.

36.   However, a subgroup within the pitcher plant mosquito population has slightly different genes that cause them to develop and reproduce later into the season.

37.   Last summer, Beth Israel halted a different gene therapy trial after three of the first six terminally ill cancer patients died.

38.   That evidence appeared in four families, suggesting a different gene is responsible in the fifth, Eiberg said.

39.   The experiment ended abruptly after the death of a teen-ager who received a different gene therapy treatment.

40.   The outcry was prompted by the death last September of a Phoenix teen-ager who had volunteered for a different gene experiment.