DNA methylation is used in some genes to differentiate which gene copy is inherited from the father and which gene copy is inherited from the mother, a phenomenon known as imprinting. Histones are proteins that are the primary components of chromatin, which is the complex of DNA and proteins that makes up chromosomes.his is the type of epigenetic change that is responsible for the inactivated X chromosome of females. In contrast, methylation of a different lysine (K4) on the same histone (H3) is a marker for active genes (Egger et al ., 2004).
Perceptual adaptation is a phenomenon that occurs for all of the senses, including smell and touch. An individual can adapt to a certain smell with time.
Sensory adaptation is the process by which our brain cells become less sensitive to constant stimuli that are picked up by our senses. This process occurs for all the senses except for vision, which is the most important sense for humans. Sensory adaptation of vision is avoided through saccadic movements of the eye. Sensory adaptation is important for daily functioning because it allows our attention to be freed to detect new and/or important aspects of our environment without being distracted by aspects of it that are constantly there.