Rainbow

Rainbow clusters and assembles restriction-site associated DNA sequencing (RAD-seq) paired-end reads to produce de novo RAD locus contigs and haplotypes for population-genomic analyses.

Key Features:

• Paired-end read clustering: Clusters paired-end short reads into groups based on unique tags.
• Spaced seed method: Uses a spaced seed method to organize reads while tolerating sequencing errors.
• Error, heterozygosity, and repeat handling: Accommodates sequencing errors, varying levels of heterozygosity, and repetitive sequences during clustering.
• Haplotype subdivision: Employs a heterozygote-calling-like top-down strategy to divide potential groups into haplotypes.
• Guided tree and merging: Constructs a guided tree and merges sibling leaves in a bottom-up manner when they exhibit sufficient similarity.
• Similarity assessment: Assesses similarity by comparing the second reads of RAD segments to collapse heterozygous sequences and distinguish repeats.
• Local assembly: Uses a greedy algorithm to locally assemble merged reads into contigs.
• Multiple assembly outputs: Produces both optimal and suboptimal assembly results.
• Performance: Implemented in C and reported as ultra-fast and memory-efficient for RAD-seq data.

Scientific Applications:

• RAD-seq de novo assembly: Assembly of RAD loci from next-generation sequencing RAD-seq datasets.
• Haplotype reconstruction: Reconstruction of haplotypes and resolution of heterozygous alleles within RAD loci.
• Repeat discrimination: Distinguishing repetitive sequences from allelic variation in RAD segments.
• Population genomics: Analyses of genetic diversity and structure, demonstrated by simulation studies and real guppy RAD-seq datasets.

Methodology:

Clusters paired-end reads using a spaced seed method based on unique tags; applies a heterozygote-calling-like top-down subdivision into haplotypes; constructs a guided tree and merges sibling leaves bottom-up by comparing second reads of RAD segments; assembles merged reads into contigs with a greedy algorithm and reports optimal and suboptimal assembly results; implemented in C.