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.
By Jennifer Kennedy. Definition: An adaptation is a physical or behavioral characteristic that has developed to allow an organism to better survive in its environment.Adaptations are the result of evolution, and may occur when a gene mutates, or changes by accident.xamples: One physical adaptation used in the intertidal zone is a crab's hard shell, which protects it from predators, drying out and being crushed by waves. A behavioral adaptation in the oceans is the use of loud, low-frequency calls by fin whales to communicate with other whales over great distances.