Dahyun week11

Epigenetics:
In biology, epigenetics is the study of heritable traits, or a stable change of cell function, that happen without changes to the DNA sequence.
Epigenetics usually involves a change that is not erased by cell division, and affects the regulation of gene expression. Such effects on cellular and physiological phenotypic traits may result from environmental factors, or be part of normal development.
 

A living organism possesses identical genetic information, yet the expression of genes varies across cells due to interactions within the cell with various molecules. The gene expression is regulated and can change depending on the molecular density within the cell.

The mechanism operates as follows: DNA is read into RNA and proteins are synthesized by ribosomes. At this point, epigenetic changes can stimulate or suppress the expression of specific genes, thus influencing protein production. Chemical marks attached to DNA or the proteins surrounding DNA can either inhibit or stimulate gene expression. The marks attached to genes are referred to as an eigenome. Epigenomes, like methyl groups, can suppress trait expression by attaching to genes and interfering with gene recognition mechanisms. They can also increase DNA's cohesiveness to prevent access and thus block expression. Conversely, gene expression can be stimulated by loosening DNA, increasing the number of binding proteins and aiding the decoding process.

Epigenetic variations differ among individuals and even among cells within the same individual. Cells derived from a master gene undergo different epigenetic changes during the differentiation process, leading to diverse gene expressions and hence, differentiation into various types of cells with different protein structures.

Epigenomes are influenced by diet, chemicals, and drugs. Such environmental factors can lead to the attachment of epigenetic markers to DNA, potentially preventing the expression of genes that suppress cancer, thereby increasing the risk of cancer.

Typically, epigenetic markers are erased during the formation of reproductive cells. However, some survive and can be passed on to offspring.

ref: https://www.youtube.com/watch?v=_aAhcNjmvhc&t=11s