Targeted de novo phasing and long-range assembly by template mutagenesis

Area of Science:

• Genomics
• Molecular Biology
• Bioinformatics

Background:

• Short-read sequencing offers cost-effective, high-accuracy DNA data.
• However, short reads are insufficient for assembling complex genomic regions and phasing distant heterozygous sites.

Purpose of the Study:

• To develop novel protocols and algorithms for haplotype-phased genome assembly using only short reads.
• To achieve ultra-low error rates in assemblies of long DNA regions (≥10 kb).

Main Methods:

• Imprinting template DNA with a unique mutation pattern (cytosine to uracil conversion).
• Generating sequencing libraries from both mutated and unmutated templates.
• Utilizing de Bruijn graphs and paired-end reads for assembly and error correction.

Main Results:

• Developed a method to produce haplotype-phased assemblies with per-base error rates below 10⁻⁹.
• Successfully assembled and phased three genomic intervals, including the HLA-B gene, in a nuclear family.
• Demonstrated the feasibility of long-range phasing and assembly using only short reads.

Conclusions:

• This novel short-read-only approach overcomes limitations of current sequencing technologies for complex genomic regions.
• Enables accurate haplotype phasing and assembly, crucial for genetic studies and diagnostics.
• Paves the way for advanced genomic analyses previously requiring long-read sequencing.