What are pseudogenes?
Pseudogenes are genomic DNA sequences similar to normal genes but non-functional; they are regarded as defunct relatives of functional genes.
What causes pseudogenes to arise?
There are two accepted processes during which pseudogenes may arise:
• duplication – modifications (mutations, insertions, deletions, frame shifts) to the DNA sequence of a gene can occur during duplication. These disablements can result in loss of gene function at the transcription or translation level (or both) since the sequence no longer results in the production of a protein. Copies of genes that are disabled in such a manner are termed non-processed or duplicated pseudogenes.
• retrotransposition – reverse transcription of an mRNA transcript with subsequent re-integration of the cDNA into the genome. Such copies of genes are termed processed pseudogenes. These pseudogenes can also accumulate random disablements over the course of evolution.