Age-correlated changes in the DNA template in the nematode Caenorhabditis elegans

Analysis of DNA from the nematode Caenorhabditis elegans demonstrated a number of significant age-correlated changes. The number of single-strand breaks as assayed by an in vitro assay procedure using Escherichia coli DNA polymerase I increased significantly with age. There was also an exponential increase in the amount of 5-methylcytosine in C. elegans DNA as the worm matured and aged. Furthermore, DNA isolated from older worms exhibited reduced transcriptional capacity when assayed in a HeLa cell in vitro transcription system. Finally, a biological assay to determine age-correlated changes in the DNA of aging sperm demonstrated a significant reduction in the capacity of the sperm to support zygotic development as the age of the male increased. These findings demonstrated significant age-correlated alterations and modifications occurring in the DNA template of the nematode, and their implications to the aging process are discussed.