A longitudinal study of epigenetic variation in twins

Area of Science:

• Epigenetics
• Developmental Biology
• Behavioral Genetics

Background:

• DNA methylation is a crucial epigenetic mechanism regulating gene expression during development.
• Aberrant DNA methylation patterns are linked to phenotypic variation and disease risk.
• The relative contributions of heritability and environment to DNA methylation variability remain unclear.

Purpose of the Study:

• To investigate the influence of genetic and environmental factors on DNA methylation in specific genes.
• To examine the stability of DNA methylation over time in early childhood.
• To assess the role of longitudinal research in understanding epigenetic modifications.

Main Methods:

• Quantitative DNA methylation analysis was performed on promoter regions of DRD4, SLC6A4/SERT, and MAOA genes.
• DNA samples were collected from 182 individuals (46 MZ twin-pairs, 45 DZ twin-pairs) at ages 5 and 10 years.
• Longitudinal-developmental study design was employed to track changes over time.

Main Results:

• DNA methylation differences were observed in early childhood, even among genetically identical twins.
• Individual differences in DNA methylation were found to be unstable over the study period.
• Environmental factors were identified as significant contributors to interindividual DNA methylation variability.
• The impact of environmental influences varied across different genomic loci.

Conclusions:

• Epigenetic modifications, specifically DNA methylation, are influenced by environmental factors from early childhood.
• The dynamic nature of DNA methylation underscores the importance of studying these changes longitudinally.
• Understanding the interplay between genetics, environment, and epigenetics is crucial for comprehending developmental trajectories and disease susceptibility.