Template switching can create complex LTR retrotransposon insertions in Triticeae genomes

Area of Science:

• Molecular Biology
• Genetics
• Plant Science

Background:

• Long terminal repeat (LTR) retrotransposons replicate via transcription and reverse transcription.
• Integrated DNA copies are prone to recombination, forming complex elements with shared LTRs.
• Previously, heterologous recombination between adjacent elements was the presumed mechanism for complex element formation.

Purpose of the Study:

• To investigate an alternative mechanism for the generation of complex LTR retrotransposon elements.
• To explore the role of template switching in creating novel genomic structures.

Main Methods:

• Analysis of retrotransposon replication and integration processes.
• Investigating mechanisms of complex element formation in plant genomes.

Main Results:

• Evidence presented for abnormal template switching during reverse transcription as a novel mechanism for creating complex elements.
• Template switching results in the fusion of two parent sequences into a large daughter element.
• This fused element is subsequently inserted into the genome.

Conclusions:

• Complex elements are integrated into the genome structure of Poaceae plants, particularly Triticeae.
• Arabidopsis plants do not feature these specific complex elements.
• Retrotransposon dynamics and their impact on genome structure are lineage-specific.