BAC To BAC Based Sequence Assembly Of Bread Wheat Chromosome 7B

The international wheat genome sequencing consortium (IWGSC) aims to produce a publicly available reference sequence of the 17Gbp hexaploid wheat genome through sequencing of single isolated chromosome arms. Norway is sequencing the chromosome 7B short (7BS) and long (7BL) arm utilizing a minimum tiling path (MTP) BAC-by-BAC sequencing strategy. Here we present the 7B preliminary sequencing and assembly results.  Here we present the data for 7BS, for which a BAC library consisting of 22,000 clones with an average insertion size of 185Kb was constructed. Fingerprinting generated an MTP consisting of 3039 BACs in 255 contigs. Sequencing of the 7BS MTP-BACs  produced 105.000 contigs covering ~450Mb, with a contig-N50 of 12 Kb. Furthermore, scaffolding of assemblies from these MTP BACs with three mate-pair libraries improved the N50 to 24 Kb. Utilizing both synteny and genetic mapping data, >60% of the BAC-contigs were anchored to the physical map. We also used CGH-based genotyping of presence-absence variation to anchor 1473 sequences to 2 chromosome deletion bins.