Epigenetics and Gene Expression

Flashcards covering the mechanisms of DNA methylation, histone acetylation, and the general principles of epigenetics.

What is the definition of epigenetics provided in the notes?

The modification of gene expression without modifying the DNA sequence.

What happens when DNA is in a decondensed (open) state?

RNA polymerase can pass, leading to transcription, protein production, and the gene being expressed.

What happens when DNA is in a very condensed (compact) state?

RNA polymerase is blocked, resulting in no transcription, no protein production, and the gene being turned off (éteint).

What chemical group is added during the process of methylation?

$$CH_3$$

Where are the groups added during methylation, and what is the outcome for the gene?

The groups are added to the DNA, making it more condensed and resulting in less transcription and less protein production, effectively turning the gene off.

What chemical group is added during the process of acetylation?

$$COCH_3$$

Where are the groups added during acetylation, and what is the outcome for the gene?

The groups are added to the histones, making the DNA less condensed and resulting in more transcription and more protein production, effectively activating the gene (on).

How is penetrance defined in the lecture notes?

The percentage (%) of individuals who express the phenotype.

What is the definition of heritability?

The part of variations that is due to genes.

According to the summary, what factors contribute to the phenotype besides genes?

Environment and Chance (Hasard).