PhylDiag: identifying complex synteny blocks that include tandem duplications using phylogenetic gene trees

Area of Science:

• Comparative genomics
• Bioinformatics
• Evolutionary biology

Background:

• Genomes contain conserved synteny blocks, regions with conserved gene order and orientation, reflecting ancestral gene arrangements.
• Accurate identification and quantification of synteny blocks are crucial for understanding genome evolutionary history.

Purpose of the Study:

• To introduce PhylDiag, a novel software for statistically identifying significant synteny blocks in pairwise eukaryotic genome comparisons.
• To improve the detection of synteny blocks by accounting for gene deletions, orientations, tandem duplicates, and de novo gene births.

Main Methods:

• PhylDiag utilizes gene trees to define gene homologies, enabling the consideration of gene deletions as synteny-breaking events.
• The software incorporates gene orientations, tandem duplicates, and lineage-specific gene births into its analysis.
• It returns synteny blocks with theoretically estimated maximum gap sizes and includes statistical validation for identified blocks.

Main Results:

• PhylDiag successfully identifies statistically significant synteny blocks in pairwise eukaryotic genome comparisons.
• The software demonstrates robustness in detecting small synteny blocks even in the presence of insertions, deletions, annotation errors, or micro-inversions.
• Benchmarking revealed PhylDiag's effectiveness compared to existing methods like i-ADHoRe 3.0 on real and simulated data.

Conclusions:

• PhylDiag is a user-friendly tool for identifying synteny blocks, enhanced by graphical display utilities and a theoretically estimated gap parameter.
• The study identified the most relevant distance metric for calculating 2D-distances between homologies.
• PhylDiag advances the field of comparative genomics by providing a more accurate and comprehensive method for analyzing genome evolution.