Pseudogenes: Introduction, Types, Features


Genes, also labelled as “junk” DNA, are inheritable genetic elements whose sequence are naturally similar to functional genes. However, they do not code for protein because they lack coding potential due to the presence of disruptive mutations such as frame shifts, premature stop codons, internal deletion or insertion relative to the normal sequence, Hence, they are thought to be non-functional.

Due to a disrupted open reading frame (ORF) they are unable to produce a functional protein and unable to produce an RNA transcript.


Based on the mechanism of their synthesis, pseudogenes can be categorized into three large groups:

Processed pseudogenes

created by retro-transposition of mRNA from functional protein-coding loci back into the genome

Duplicated pseudogenes (also referred to as unprocessed),

It is derived from duplication of functional genes.

Unitary pseudogenes

This type of pseudogenes is derivate through in-situ mutations in previously functional protein-coding genes


Pseudogenes have long been considered as non-functional genomic sequences. About 20,000 pseudogenes have been reported in the human genome. It was considered ans junk DNA since long decade.

However, evidence of transcription and conservation of some pseudogenes led to the speculation that they might be functional and several estimates of the number of transcribed pseudogenes have been published in recent years. In the recent studies, it has shown that, in some cases, expression of the pseudogenes into their RNA products can also perform critical controlling.

Leave a Comment

Your email address will not be published. Required fields are marked *