(From PhysOrg.com). Researchers have discovered more genes related to the mechanisms by which calorie restriction increases longevity: "Deleting Hst2 and Sir2 blocked most of the beneficial effect of caloric restriction. When Hst2 was overexpressed, so the gene was more active than normal, the yeast lived longer than normal. A third gene, Hst1, appears to act when both Sir2 and Hst2 are missing. Sir2 and the newly identified Hst genes account for all of the life-prolonging effects of caloric restriction in yeast." While yeast may or may not be a good place to start, it seems that scientists are on the verge of completely understanding calorie restriction. This bodes well for the prospect of therapies that can produce the same beneficial effects on healthy life span.