HAlign-G: rapid and low-memory multiple-genome aligner for large-scale closely related genomes.

HAlign-G is a fast and memory-efficient tool for large-scale multiple genome alignment. Using BWT-FM-LIS with an optimized K-band algorithm and star alignment strategy, it supports intra-species (HAlign-G1) and cross-species (HAlign-G2) alignment. Benchmarks show superior accuracy, efficiency, and memory use compared with existing methods. HAlign-G1 excels in speed and quality for intra-species data for multiple sequence alignment, while HAlign-G2 offers higher accuracy and structural variant detection for multiple genome alignment. Both versions handle millions of SARS-CoV-2 genomes and thousands of human chromosomes, enabling reliable evolutionary studies and supporting the construction of more stable phylogenetic trees, while enhancing Progressive Cactus performance.