Minimap2: pairwise alignment for nucleotide sequences.

Motivation: Recent advances in sequencing technologies promise ultra-long reads of similar to 100 kb in average, full-length mRNA or cDNA reads in high throughput and genomic contigs over 100 Mb in length. Existing alignment programs are unable or inefficient to process such data at scale, which presses for the development of new alignment algorithms. Results: Minimap2 is a general-purpose alignment program to map DNA or long mRNA sequences against a large reference database. It works with accurate short reads of >= 100 bp in length, >= 1 kb genomic reads at error rate similar to 15%, full-length noisy Direct RNA or cDNA reads and assembly contigs or closely related full chromosomes of hundreds of megabases in length. Minimap2 does split-read alignment, employs concave gap cost for long insertions and deletions and introduces new heuristics to reduce spurious alignments. It is 3-4 times as fast as mainstream short-read mappers at comparable accuracy, and is >= 30 times faster than longread genomic or cDNA mappers at higher accuracy, surpassing most aligners specialized in one type of alignment.