genome topology network

genome topology network analyzes bacterial genomes by comparing gene order topology to infer phylogenetic relationships and characterize genome structural differences, with applications to group B Streptococcus (GBS) genomes.

Key Features:

• Phylogenetic Analysis: Constructs phylogenetic trees from gene order topology and, in a case study of 51 GBS genomes from the NCBI database, partitioned them into six main clades with higher resolution than single nucleotide polymorphism (SNP)-based methods.
• Gene Family Differentiation: Identifies node-specific gene family associations and links them to functional categories such as carbohydrate transport and metabolism, replication, recombination and repair, and translation.
• Draft Genome Compatibility: Locates synteny blocks within draft assemblies to enable analysis of incomplete genomes.
• Gene Family Clustering: Uses the Markov Cluster Algorithm (MCL), as implemented in tools like orthoMCL, to cluster genes into families.
• Bootstrap Testing for Clade Verification: Applies bootstrap testing to assess the credibility and support of identified clades and their relationships.
• Complementary Evolutionary Information: Reports differences in gene connections between species or clades to complement SNP-based analyses with genome topology data.

Scientific Applications:

• Bacterial phylogeny reconstruction: Reconstructs bacterial phylogenies from gene order topology, offering an alternative and sometimes higher-resolution view compared with SNP-based methods.
• Comparative genomics of GBS: Analyzes genomic architecture and clade structure in group B Streptococcus (GBS), demonstrated with 51 genomes from the NCBI database.
• Identification of functional drivers: Links gene order variation to functional categories to identify genes involved in clade differentiation, pathogenicity, adaptation, and resistance.
• Draft genome analysis: Enables comparative and evolutionary studies using both complete and draft genome assemblies via synteny block detection.

Methodology:

Constructs phylogenetic trees from genome topology; detects synteny blocks in draft genomes; clusters gene families using the Markov Cluster Algorithm (MCL); and performs bootstrap testing to verify clade support.