DNA methylation is an indicator of the impact of environmental factors on health, and some forms of DNA methylation due to environmental factors are long-lasting, while others are transient. It occurs when a methyl group gets added to the fifth carbon of cytosine in regions with cytosine and guanine (CpG) repeats. Studies have reported that cigarette smoking results in both persistent and transient DNA methylation at CpG sites across the genome. DNA methylation patterns in specific genes have also been observed in groups such as adolescents who frequently use cannabis and patients who are dependent on cannabis.
Conclusions: Overall, the findings reported substantial DNA methylation changes in CpG sites across five genes that play significant roles in health and disease. While four of these CpG sites overlap with those associated with cigarette smoking, cannabis use by itself is also linked to DNA methylation in one gene. The results highlight the utility of DNA methylation as a tool to understand the interactions between environmental factors and genetics and emphasize the need for further research on the impact of cannabis use on health outcomes.
(Source: Cannabis use alters DNA methylation, with implications beyond smoking effects (news-medical.net) For the Complete Published Research Trans-ancestry epigenome-wide association meta-analysis of DNA methylation with lifetime cannabis use | Molecular Psychiatry (nature.com)
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