Genomic 5-methyldeoxycytidine decreases with age

Area of Science:

• Epigenetics and aging research.
• Comparative genomics and molecular biology.

Background:

• DNA 5-methyldeoxycytidine (5-mdC) is crucial for gene regulation.
• Loss of 5-mdC with age may impair cellular function and contribute to aging.

Purpose of the Study:

• To quantify DNA 5-mdC loss in aging rodents.
• To investigate the relationship between 5-mdC loss rate and lifespan.
• To examine 5-mdC changes in human cells with age.

Main Methods:

• DNA isolation from tissues of Mus musculus and Peromyscus leucopus of various ages.
• Quantification of 5-mdC content in isolated DNA.
• Analysis of 5-mdC loss rates and correlation with lifespan.
• Assessment of 5-mdC in cultured human bronchial epithelial cells.

Main Results:

• Mus musculus lost DNA 5-mdC at approximately 4.7 x 10^4 sites/month.
• Peromyscus leucopus lost DNA 5-mdC at approximately 2.3 x 10^4 sites/month.
• The rate of 5-mdC loss was inversely proportional to the species' lifespan.
• Similar age-related 5-mdC decline was noted in human cells.

Conclusions:

• DNA 5-mdC loss is a hallmark of aging in mammals.
• The rate of epigenetic drift, measured by 5-mdC loss, correlates with longevity.
• Epigenetic alterations in 5-mdC may be a conserved mechanism in aging across species.