Methods for accurate quantification of LTR-retrotransposon copy number using short-read sequence data: a case study...

Area of Science:

• Genomics
• Bioinformatics
• Molecular Biology

Background:

• Transposable elements (TEs) are mobile DNA sequences prevalent in eukaryotic genomes.
• Their activity influences genome structure and function, but their repetitive nature complicates analysis, especially with short-read sequencing.
• Accurate characterization of TEs is crucial for understanding genome evolution and dynamics.

Purpose of the Study:

• To develop and validate a novel method for estimating transposable element (TE) copy number from short-read sequencing data.
• To compare the effectiveness of reference-based and de novo approaches for TE analysis in plant genomes.
• To investigate TE landscape variations within and between closely related plant species.

Main Methods:

• Development of a computational method to estimate TE copy number from short-read sequences.
• In silico analysis using the Sorghum bicolor reference genome with both reference-based and de novo strategies.
• Application of the method to real short-read data from Sorghum bicolor and Sorghum propinquum accessions.

Main Results:

• The developed method showed high accuracy in estimating TE copy numbers, closely matching annotated values in silico.
• Both reference-based and de novo methods successfully identified and ranked abundant TE families.
• De novo approaches captured qualitative variation but underestimated ancient TE families; reference-based mapping across species had limitations.

Conclusions:

• The new method provides a reliable way to estimate TE copy number from short-read data.
• Reference-based analyses are optimal for within-species TE comparisons.
• De novo approaches are more suitable for analyzing TE content in evolutionarily divergent species.