Epigenetikk

Epigenetics is the study of heritable changes in gene expression that do not involve changes to the underlying DNA sequence. These changes, known as epigenetic modifications, can affect how genes are read by cells and can be influenced by environmental factors and lifestyle choices. Epigenetic modifications include DNA methylation, histone modification, and non-coding RNA.

DNA methylation is a common epigenetic modification where a methyl group is added to a DNA molecule, typically at a cytosine base followed by a guanine base (CpG site). This modification can silence gene expression by preventing transcription factors from binding to the DNA. DNA methylation patterns can be inherited through cell division and can be influenced by environmental factors such as diet, stress, and exposure to toxins.

Histone modification involves changes to the proteins around which DNA is wound, known as histones. These modifications can alter the accessibility of DNA to transcription factors, affecting gene expression. Histones can be acetylated, methylated, phosphorylated, or ubiquinated, each of which can have different effects on gene expression.

Non-coding RNA, such as microRNA and long non-coding RNA, also plays a role in epigenetics. These molecules can regulate gene expression by binding to mRNA and preventing it from being translated into protein or by directly interacting with chromatin.

Epigenetic modifications can be reversible and can be influenced by environmental factors, lifestyle choices, and aging. They can also be heritable, meaning that they can be passed down to daughter cells during cell division. Epigenetics has been linked to a variety of diseases, including cancer, and is an active area of research in the fields of medicine and biology.