51.   A single gene would be easier to trace than a combination and would make a better starting point for research, Dr. Christiano said.

52.   A modern gene is a chemical text with a thousand or more letters.

53.   A researcher who finds that a particular gene is involved in human disease can compare its DNA sequence with those in the worm genome data base.

54.   Again, an individual gene is less important than the network in which it operates.

55.   Alcohol also contributes to obesity and to problems with liver function, which help trigger diabetes if certain genes are present.

56.   But a gene is not the sole determinant of a particular effect.

57.   But ensuring the gene is spread in precise quantities remains difficult.

58.   But genes are not destiny.

59.   But fruit fly genes are of no direct medical value, and the two sides were able to share credit and make their data public without acrimony.

60.   But genes are probably not the only reason people have high blood pressure.