This disclosure provides methods and compositions for long fragment read sequencing. Technology is described for preparing long fragments of genomic DNA, for processing genomic DNA for long fragment read sequencing methods, as well as software and algorithms for processing and analyzing sequence data. Combinatorial oligonucleotide bar codes are used to label fragments from nearby portions of the genome, which facilitate computational assembly of sequence reads to obtain the genome sequence. This improves efficiency and accuracy of sequencing, whereby an entire sequence can be obtained from fragments that constitute a lower coverage amount of the genome.