Aging may be less about specific 'aging genes' and more about how long a gene is. Many of the changes associated with aging could be occurring due to decreased expression of long genes, say researchers. A decline in the expression of long genes with age has been observed in a wide range of animals, from worms to humans, in various human cell and tissue types, and also in individuals with neurodegenerative disease. Mouse experiments show that the phenomenon can be mitigated via known anti-aging factors, including dietary restriction.