epigenetilised

Epigenetilised changes refer to alterations in gene activity that do not involve changes to the DNA sequence. They are mediated by biochemical marks and structural changes to chromatin that regulate transcription. These modifications can be maintained through cell divisions and contribute to cell identity and development.

Major mechanisms include DNA methylation, histone modifications, and chromatin remodeling. DNA methylation typically occurs at cytosines in CpG dinucleotides and is generally associated with gene repression. Histone tails can be modified by methylation, acetylation, and other marks, influencing chromatin compaction. Non-coding RNAs can guide gene silencing or activation.

Epigenetilised states are modulated by environmental factors such as nutrition, toxins, stress, and aging, and play roles in development, imprinting, and X-chromosome inactivation. While most epigenetic marks are erased during gametogenesis and early embryo development, some can be transmitted to subsequent generations (transgenerational epigenetic inheritance).

Researchers study these processes with techniques including bisulfite sequencing for DNA methylation, chromatin immunoprecipitation followed by sequencing (ChIP-seq) for histone modifications, ATAC-seq for chromatin accessibility, and RNA sequencing to link epigenetic states with gene expression.