A new approach for the identification of processed pseudogenes

Area of Science:

• Genomics
• Bioinformatics
• Molecular Biology

Background:

• Processed pseudogenes originate from retrotransposition of mature messenger RNAs (mRNAs).
• They are often considered non-functional "junk DNA" due to lack of promoters and transcription.
• Despite this, they hold valuable transcriptome information, particularly for species with limited expressed sequence tag (EST) data.

Purpose of the Study:

• To develop a novel computational method for identifying processed pseudogenes and their parent genes.
• To overcome limitations of existing methods that require prior knowledge of mRNA sequences.
• To enhance genome annotation by leveraging pseudogene information.

Main Methods:

• Development of the REtrotransposed Gene EXPlorer (REGEXP) pipeline.
• Systematic identification of retrotransposition events without relying on a priori mRNA sequences.
• Validation of predicted pseudogenes and genes using RT-polymerase chain reaction (RT-PCR).

Main Results:

• Identified 2288 processed pseudogenes in the human genome, with good overlap with existing databases (ENSEMBL, VEGA, pseudogene.org).
• Traced pseudogenes back to 987 source genes, detecting signatures of alternative splicing in some cases.
• Validated novel pseudogene predictions, demonstrating high specificity and accuracy of the REGEXP method.
• Achieved similar results in the mouse genome.

Conclusions:

• The REGEXP method effectively identifies processed pseudogenes and predicts their corresponding genes.
• It offers a valuable, specific, and potentially novel approach to genome annotation.
• REGEXP is a valuable addition to current genome annotation pipelines, especially for transcriptome analysis.