MethPhaser: methylation-based long-read haplotype phasing of human genomes

• Published in: Nature communications Vol. 15; no. 1; pp. 5327 - 12
• Main Authors: Fu, Yilei, Aganezov, Sergey, Mahmoud, Medhat, Beaulaurier, John, Juul, Sissel, Treangen, Todd J., Sedlazeck, Fritz J.
• Format: Journal Article
• Language: English
• Published: London Nature Publishing Group UK 22-06-2024; Nature Publishing Group; Nature Portfolio
• Subjects: 45/23; 631/114; 631/114/2785; 631/114/794; Cell Line; Diploids; DNA Methylation; Genetic diversity; Genetic variance; Genome, Human; Genomes; Haplotypes; Heredity; Homozygosity; Humanities and Social Sciences; Humans; Inactivation; multidisciplinary; Mutation; Nucleotides; Phenotypes; Polymorphism, Single Nucleotide; Science; Science (multidisciplinary)
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-024-49588-0

The assignment of variants across haplotypes, phasing, is crucial for predicting the consequences, interaction, and inheritance of mutations and is a key step in improving our understanding of phenotype and disease. However, phasing is limited by read length and stretches of homozygosity along the genome. To overcome this limitation, we designed MethPhaser, a method that utilizes methylation signals from Oxford Nanopore Technologies to extend Single Nucleotide Variation (SNV)-based phasing. We demonstrate that haplotype-specific methylations extensively exist in Human genomes and the advent of long-read technologies enabled direct report of methylation signals. For ONT R9 and R10 cell line data, we increase the phase length N50 by 78%-151% at a phasing accuracy of 83.4-98.7% To assess the impact of tissue purity and random methylation signals due to inactivation, we also applied MethPhaser on blood samples from 4 patients, still showing improvements over SNV-only phasing. MethPhaser further improves phasing across
HLA
and multiple other medically relevant genes, improving our understanding of how mutations interact across multiple phenotypes. The concept of MethPhaser can also be extended to non-human diploid genomes. MethPhaser is available at
https://github.com/treangenlab/methphaser
.
The assignment of genetic variants to the two copies of the genome present in cells (phasing) is crucial for predicting the consequences, interaction and inheritance of variants, but is limited by the length of sequencing reads and stretches of homozygosity in the genome. Here the authors develop a method that utilizes DNA methylation signals from Oxford Nanopore Technologies sequencing data to improve phasing.