(55) and the RNA-DNA hybrid selection methods described above). However, in this section we focus on reports from several groups that apply the programmable microarray it- self as a selective substrate for solid-phase capture-by-hybridization. Fragmentation Genomic DNA Random library Repair, adaptor ligation Target capture Adaptor-ligated fragments Custom MGS array Wash, elution Selected target region Amplification with single primer pair Enriched target region Figure 9 On array hybrid selection. In vitro shotgun libraries are generated from genomic DNA, with common adapters flanking each fragment. The library is hybridized to oligos tethered on a high-density programmable microarray. Unbound molecules are washed from the array, followed by heat-based elution of specifically hybridized material. Multitemplate PCR with primers directed at the common adaptors is used to amplify eluted target molecules before high- quences designed from the referen genome to tile region(s) of interest at sity (i.e., 1 to 10 bp spacing) for i hybridization, while excluding non repetitive sequences from considerat hybridization for ∼65 h at 42◦C, an wash steps, heat-based elution at 95◦C out to recover specifically hybridized Universal primers corresponding to mon adaptors are used for PCR amp after which the target-enriched shotg can be sequenced. Albert et al. (2) designed and several capture arrays, one focused o ing 6726 discontiguous exons and ad quences from 660 genes (total targ 5 Mb), and the remainder focused on ous intervals of varying sizes at the B cus (200 kb, 500 kb, 1 Mb, 2 Mb, a with the same array format but differ ties of probe spacing. With three re the exon-focused array, sequencing da to 115 Mb of sequence generated fro richment libraries by 454 sequencin relatively consistent performance, wi 77% of reads mapping to targets, an 96% of targets overlapped by at lea For capture directed at a contiguo (200 kb to 5 Mb), the fraction of re ping to the target appeared to be with the size of the target, i.e., 14% kb target vs 64% for a 5-Mb target. given that the 200-kb target is 25-fo than the 5-Mb target, the calcula Annu. Rev. Genom. Human Genet. 2009.10:263-284. Downloaded from arjournals.annualrevie by EMORY UNIVERSITY on 09/29/09. For personal use only.