Identification and characterization of occult human-specific LINE-1 insertions using long-read sequencing technology

Area of Science:

• Genomics
• Molecular Biology
• Bioinformatics

Background:

• Long Interspersed Element-1 (LINE-1) retrotransposition is a source of genetic variation and can cause genetic disorders.
• Existing short-read whole genome sequencing (WGS) methods struggle to detect LINE-1 insertions in complex genomic regions.

Purpose of the Study:

• To develop and utilize a computational tool (PALMER) for identifying human-specific LINE-1 (L1Hs) insertions.
• To compare the efficacy of short-read versus long-read sequencing for L1Hs insertion detection.

Main Methods:

• Developed the computational tool PALMER for L1Hs insertion identification.
• Utilized PacBio long-read sequencing data for analysis.
• Analyzed L1Hs insertion detection rates in single-cell WGS experiments.

Main Results:

• Identified 203 non-reference L1Hs insertions in the NA12878 genome using PALMER.
• Discovered 90 L1Hs insertions missed by previous short-read studies using long-read sequencing.
• Observed significant variation in detection rates due to amplification biases in single-cell WGS.

Conclusions:

• Standard short-read sequencing approaches frequently miss L1Hs insertions.
• Long-read sequencing significantly enhances the detection of L1Hs insertions in individual genomes.
• Computational tools like PALMER are crucial for accurate LINE-1 insertion identification.