Description: Methylation is a fundamental biochemical process that involves the addition of a methyl group (-CH3) to the DNA molecule, specifically to cytosines within the DNA sequence. This process is crucial for the regulation of gene expression, as it can silence genes without altering the underlying DNA sequence. DNA methylation is primarily carried out by enzymes called methyltransferases, which transfer methyl groups from donors such as S-adenosylmethionine (SAM) to the DNA bases. Methylation can influence the structure of chromatin, thereby affecting the accessibility of DNA to transcription factors and, consequently, gene activity. This mechanism is essential in biological processes such as embryonic development, cellular differentiation, and response to environmental factors. Additionally, DNA methylation plays an important role in genomic stability and in preventing the expression of mobile genetic elements. Alterations in methylation patterns have been associated with various diseases, including cancer, highlighting its relevance in molecular biology and medicine. In summary, methylation is a key epigenetic mechanism that modulates gene expression and has significant implications for health and disease.
History: DNA methylation was discovered in the 1970s when it was identified that the methylation of cytosines in mammalian DNA was a common phenomenon. In 1975, the work of Arthur Riggs and other researchers demonstrated that DNA methylation could influence gene expression. Since then, research on methylation has grown exponentially, especially with the advancement of sequencing techniques and genomic analysis in recent decades.
Uses: DNA methylation is used in various applications, including research in epigenetics, disease diagnosis, and personalized medicine. It is employed to study gene expression patterns in different cell types and tissues, as well as to identify biomarkers in diseases such as cancer. Additionally, it is used in agriculture to develop more resilient crops by modifying methylation patterns.
Examples: An example of the use of DNA methylation is in cancer detection, where methylation patterns in tissue samples are analyzed to identify changes that may indicate the presence of tumors. Another example is the use of methylation in developmental studies, where researchers investigate how methylation affects cellular differentiation during embryonic development.
