What is the difference between Euchromatin and Heterochromatin?

Heterochromatin and Euchromatin are types of chromatin's higher-order structure. Heterochromatin has two types which are constitutive and facultative heterochromatin. Heterochromatin has a tightly packed form of DNA that exhibits heteropycnosis while Euchromatin has a loosely packed form of DNA and does not exhibit heteropycnosis.

Euchromatin has a low DNA density which can be found in prokaryotes and eukaryotes, while heterochromatin has a high DNA density; it can be found in the eukaryotes only. Heterochromatin is formed in the periphery of the nucleus. It actively participates in the transcriptional activity while Euchromatin is formed in the inner body of the nucleus and has no or little transcriptional activity.

In heterochromatin, the DNA is said to be tightly bound. On the other hand, the DNA in euchromatin is lightly bound. Heterochromatin refers to a form of chromatin whose packing takes place densely. The description of their packing is the significant difference between the two.

Euchromatin refers to a type of chromatin. The occurrence of euchromatin typically means that there are active cells characterized in a transitional manner, which means that they are transcribing DNA to mRNA in an active manner. Heterochromatin exists on the outside of the nucleus. They only occur in eukaryotic cells, while euchromatin resides in the inner body of the nucleus.

They occur in eukaryotic and prokaryotic cells. Heterochromatin demonstrates no change in the phenotype of an organism; however, gene regulation is possible. Euchromatin variation may occur because in DNA at the genetic process, and genetic transcription occurs.

Chromatin is a component of the nucleus. It consists of protein and DNA. There are two forms it namely the euchromatin and the heterochromatin. When it is stained and watched with the aid of a microscope, hetero chromatins are darkly colored bands while the euchromatin is the bands with light-colored. When the staining is darker, it means the DNA packaging is tighter.

Therefore DNA packaging is tighter in heterochromatin than in Euchromatin. Heterochromatin’s coiled regions are compact, while euchromatin coiled regions are loose. Heterochromatin has more DNA than euchromatins. Replication in Euchromatin is early, while the replication is heterochromatin is late.

Euchromatin is usually found in eukaryotes, cells having nuclei, and the prokaryotes, cells that do not have nuclei. Heterochromatin can only be found in the eukaryotes. The functions of the euchromatin and the heterochromatin include the transcription of DNA, expression of the gene, and gene repression.