Euchromatin

Euchromatin are chromosome material which does not stain strongly except during cell division. It represents the major genes and is involved in transcription. Euchromatin comprises the most active portion of the genome within the cell nucleus (92% of the human genome is euchromatic).

When observed under an optical microscope, euchromatin appears as light-colored bands. This lighter staining is due to the less compact structure of euchromatin. They also participate in the active transcription of DNA to mRNA products.

Heterochromatin

Heterochromatin are chromosome material of different density from normal (usually greater), in which the activity of the genes is modified or suppressed. Heterochromatin is usually localized to the periphery of the nucleus and it stains intensely, indicating tighter packing.  Also, it mainly consist of genetically inactive satellite sequences and many genes are repressed to various extends, although some cannot be expressed in euchromatin at all.

Euchromatin Vs. Heterochromatin: The Differences

Also Read: Difference Between Replication And Transcription

Definition          

Euchromatin is the loosely packed form of DNA in the chromosome while Heterochromatin is the tightly packed form of DNA in the chromosome.

Staining Phase

Euchromatin is lightly stained; but stained dark during the mitosis whereas heterochromatin is stained dark during the interphase.

Density of DNA

In euchromatin the density of DNA is very low whereas in heterochromatin, the density of DNA is high.

Packaging

Euchromatin consists of chromatin fibers and the DNA is wrapped around histone protein chores, hence, it is loosely packed. On the other hand, heterochromatin is tightly packed form of DNA in the chromosome.

Presence

 Euchromatin is found in the inner body of the nucleus of prokaryotic cells as well as in eukaryotic cells. Heterochromatin is found at the periphery of the nucleus in eukaryotic cell only.

How it is affected

DNA of euchromatin is affected by genetic processes and variations in alleles while in heteromatin, the phenotype of an organism remain unchanged.

Function

Euchromatin is involved in genetic transcription and genetic variations while heterochromatin is involved in maintenance of structural integrity and regulation of gene expression.

Stickiness

Regions of euchromatin are non sticky, but the areas of heterochromatin are quite sticky.

Genetic activity

Euchromatin is genetically active. It may also be exposed to chromosomal cross over. On the other hand, heterochromatin is genetically inactive and therefore it becomes difficult for it to be exposed to chromosomal cross over.

DNA replication

Euchromatin replicates early whereas heterochromatin replicates late.

Types

A uniform type of euchromatin is found in the nucleus whereas heterochromatin is composed of two types: constitutive heterochromatin and facultative heterochromatin.

Condensation/De-condensation

In euchromatin condensation and decondensation of DNA is interchanged during the periods of the cell cycle whereas heterochromatin remains condensed during each period of cell cycle, except at DNA replication.

Transcriptional activity

Euchromatin actively participates in the process of transcription whereas heterochromatin shows little or no transcriptional activity.

Also Read: Difference Between DNA And RNA

The Difference Between Euchromatin And Heterochromatin In Tabular Form

Summary

Euchromatin are chromosome material which does not stain strongly except during cell division. It represents the major genes and is involved in transcription. Heterochromatin on the other hand,  are chromosome material of different density from normal (usually greater), in which the activity of the genes is modified or suppressed.

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