Epigenetics Overview and Processes

The complete set of DNA instructions unique to an individual.

A layer of chemical compounds that sit on top of the genome and tell it what to do.

Changes in how genes are expressed without altering the underlying DNA sequence. It involves chemical modifications like methylation and acetylation.

The process of adding a methyl group to DNA, often leading to decreased gene expression.

Differences in DNA methylation patterns between individuals can contribute to varying disease risk.

The study of how environmental factors and behavior can influence gene expression without altering the DNA sequence.

Epigenetic changes can be reversed, unlike genetic changes. They don't change the DNA sequence but can alter how the body reads it.

Epigenetic changes can turn genes "on" or "off." This is how epigenetic processes impact our health.

Addition of a methyl group (CH3) to DNA, primarily at cytosine bases, typically turning genes "off."

Process of removing the methyl group from DNA, usually "turning genes on."

A process in female mammals where one X chromosome is inactivated to balance gene expression between sexes. The Xist gene seems to play a role in selecting which chromosome is inactivated.

Chemical modifications, chromatin modifications, and non-coding RNA are all epigenetic mechanisms that influence gene expression.

Factors like heavy metals, pesticides, and viruses can cause epigenetic changes. These can impact gene expression.

Infections can change the methylation patterns of DNA and histone proteins, impacting immune system function. This can weaken the immune response, allowing the infection to persist.

Changes in epigenetic markers, like increased DNA methylation, can increase the risk of developing cancer. These changes can affect gene expression related to cell growth and division.

Epigenetic changes can be used to identify different subtypes of cancer. Abnormal methylation patterns in specific regions of the genome can help diagnose certain cancers.

A pregnant woman's diet and lifestyle can affect the epigenetic programming of the fetus. These changes can influence the child's health later in life.

The Dutch Winter Famine (1944-1945) showed that prenatal exposure to famine can lead to epigenetic changes that increase the risk of developing chronic diseases later in life.

Some epigenetic changes can be reversed by lifestyle interventions, such as dietary changes and exercise.

Epigenetics is a relatively new field but offers a promising avenue for understanding and potentially preventing diseases. Researchers are exploring epigenetic therapies for cancer and other conditions.

The process of modifying DNA by adding methyl groups, influencing gene expression. It plays a crucial role in X-chromosome inactivation, where the inactive chromosome becomes methylated, while the remaining active X chromosome remains unmethylated.

Histones are proteins that DNA wraps around. When histones are tightly packed, genes are 'off'. Loosely packed histones allow more DNA exposure, turning genes 'on'. Chemical modifications can alter histone packing.

Non-coding RNAs regulate gene expression by interacting with coding RNAs, leading to their breakdown and preventing protein production. They can also recruit proteins to modify histones, turning genes 'on' or 'off'.

Epigenetics encompasses modifications to DNA and its associated proteins that influence gene expression without altering the underlying DNA sequence. These modifications can be influenced by factors like environment and lifestyle.

Epigenetic changes happen throughout life, starting even before birth. These changes are essential in determining the fate of cells during differentiation, as different cells specialize for specific functions.

Epigenetic changes, including DNA methylation patterns, can vary with age. For example, DNA methylation levels are generally higher in newborns, gradually decreasing throughout life. This suggests that epigenetic modifications are dynamic and constantly adapting.

Not all epigenetic modifications are permanent; some can be altered in response to changes in behavior or environment. This suggests that epigenetic changes can be reversible, offering potential avenues for therapeutic interventions.

Smoking can induce epigenetic changes, particularly at certain parts of the AHRR gene. Smokers tend to have less DNA methylation at this gene compared to non-smokers. However, quitting smoking can lead to an increase in DNA methylation levels at this gene over time, potentially reaching levels similar to non-smokers.