Deletion Mutations and Biological Aging in Muscle Mass Loss

• Researchers from the University of California Los Angeles and the University of Alberta, Canada, found that deletion mutations and aberrant mitochondrial DNA expression correlate with biological aging in humans and rodents.

• Deletion mutations gradually erode the function of the mitochondrion, leading to muscle mass loss.

• The majority of the genome resides in the cell’s nucleus, while a mere five-millionth of the nuclear genome is located in the mitochondrial genome (mtDNA).

• Abnormal expression of many mitochondrial genes correlates with biological aging in humans and rodents.

• Deletion mutations create novel chimeric genes, which can interfere with the normal mRNA the cell produces from residual intact mtDNA.

• Older individuals showed a two-fold increase in chimeric mitochondrial mRNA, which were products of the mtDNA deletion events.