Haplotype Inference Using Long-Read Nanopore Sequencing: Application to GSTA1 Promoter

Area of Science:

• Genetics
• Molecular Biology
• Bioinformatics

Background:

• Accurate haplotype recovery is clinically significant but challenging in laboratories, often relying on inference.
• The GSTA1 promoter region presents specific phasing difficulties due to potentially ambiguous haplotypes.

Purpose of the Study:

• To evaluate the efficacy of Oxford Nanopore sequencing technology for phasing GSTA1 promoter haplotypes.
• To compare Oxford Nanopore sequencing results with Sanger sequencing and existing inferred haplotypes.

Main Methods:

• Utilized Oxford Nanopore sequencing on eight LCL cell lines with ambiguous haplotypes.
• Sequenced a 1336 bp PCR product of the GSTA1 promoter region, achieving an average read length of 813 bp.
• Compared phasing accuracy with Sanger sequencing and data from the 1000 Genomes Project.

Main Results:

• Oxford Nanopore sequencing successfully recovered true haplotypes for the GSTA1 promoter region.
• High accuracy (>90%) was achieved for SNPs closer than 200 bp, with over 58% accuracy for SNPs 1089 bp apart.
• Sequencing coverage was optimal in the middle of the PCR product, decreasing towards the ends.

Conclusions:

• Long-read Oxford Nanopore sequencing provides an accurate and robust method for determining true haplotypes without inference.
• Phasing success is dependent on SNP distances and frequencies, highlighting the technology's potential in clinical applications.
• The number of PCR cycles impacts hybrid haplotype generation, but not extension or annealing times.