NPGREAT

NPGREAT assembles human subtelomeric regions by integrating 10X Linked-Read data and ultralong nanopore reads to resolve segmental duplications and structural variation and improve contiguity and orientation near telomeres.

Key Features:

• Hybrid Assembly Methodology: Integrates 10X Linked-Read datasets with ultralong nanopore reads to span subtelomeric segmental duplications.
• Linked-Read Data Utilization: Identifies 1-copy subtelomere-adjacent sequences from Linked-Reads and assembles and extends them into duplication regions using Regional Extension of Assemblies using Linked-Reads (REXTAL).
• Ultralong Nanopore Reads: Maps ultralong nanopore reads containing telomeres to improve contiguity, ensure correct orientation of REXTAL contigs, and identify and correct misassemblies.
• Economical Alternative: Enhances assembly accuracy and coverage in regions with large duplications adjacent to telomeres as an alternative when high-fidelity (HiFi) longer-read datasets are not available.

Scientific Applications:

• Subtelomeric functional analysis: Enables genetic analyses of subtelomeric regions that contain gene and pseudogene families and regulate telomere length and stability by producing more complete assemblies despite segmental duplications and structural variation.
• Comparative assembly evaluation: Demonstrated on representative subtelomeres from the haploid human cell line CHM13 and shown to yield more complete assemblies than Nanopore-only methods such as SHASTA in distal subtelomere regions with low coverage.

Methodology:

Combines a 10X Linked-Read dataset with ultralong nanopore reads from the same genome (exemplified by CHM13), assembles and extends 1-copy subtelomere-adjacent sequences using REXTAL, and maps ultralong nanopore reads containing telomeres to orient and correct REXTAL contigs.