If you have this genetic characteristic, your chance of getting from age 70 to 100 increases by over threefold. Among the 70-year-old control group we studied, 8 percent have this mutation. Among the 100-year-olds, 25 to 30 percent of them have it. We will have to look at other parts of this gene to see if there are more mutations. There are other genes that also control H.D.L. and the sizes of lipoproteins, and we're looking for them. The gene that we discovered only explains 18 percent of the longevity. But it is possible that if everyone has the effect of this gene they will get to be 100. We want to explain 100 percent of the reasons for exceptional longevity. So we are looking at other genes. A very few of the oldest people we've studied actually do not have large lipoproteins and do not have any mutations that we've discovered so far.