H3K27ac

H3K27ac refers to a specific chemical modification where an acetyl group is added to the lysine amino acid at position 27 on histone H3 proteins, which help package DNA in our cells. This modification is associated with active regions of the genome, such as gene enhancers and promoters, indicating that these genes are likely turned on. Essentially, H3K27ac acts as a marker signaling which parts of the DNA are active and accessible for gene expression, playing a vital role in regulating how genes are turned on or off in different cells and conditions.