Unique haplotype structure determination in human genome using Single Molecule, Real-Time (SMRT) Sequencing of targeted full-length fosmids.
Determination of unique individual haplotypes is an essential first step toward understanding how identical genotypes having different phases lead to different biological interpretations of function, phenotype, and disease. Genome-wide methods for identifying individual genetic variation have been limited in their ability to acquire phased, extended, and complete genomic sequences that are long enough to assemble haplotypes with high confidence. We explore a recombineering approach for isolation and sequencing of a tiling of targeted fosmids to capture interesting regions from human genome. Each individual fosmid contains large genomic fragments (~35?kb) that are sequenced with long-read SMRT technology to generate contiguous long reads. These long reads can be easily de novo assembled for targeted haplotype resolution within an individual’s genomes. The P5-C3 chemistry for SMRT Sequencing generated contiguous, full-length fosmid sequences of 30 to 40 kb in a single read, allowing assembly of resolved haplotypes with minimal data processing. The phase preserved in fosmid clones spanned at least two heterozygous variant loci, providing the essential detail of precise haplotype structures. We show complete assembly of haplotypes for various targeted loci, including the complex haplotypes of the KIR locus (~150 to 200 kb) and conserved extended haplotypes (CEHs) of the MHC region. This method is easily applicable to other regions of the human genome, as well as other genomes.