Diversity Arrays Technology (DArT^®)

The sequential nature of gel-based marker systems entails low throughput and high costs of analysis. Commonly-used marker technologies such as SNP and SSR depend on sequence information. Diversity Arrays Technology (DArT^®), which Triticarte^® applies to cereals, circumvents these limitations. DArT^® detects single base changes and INDELs without relying on sequence information, yet produces sequence-ready markers. Its high multiplexing level enables high throughput.

Triticarte^® uses an array of individualised fragments of genomic representations of wheat and barley, prepared from pools of genotypes that cover the genetic diversity of each species. Representations of varieties to be genotyped are labelled and hybridised to the array. The polymorphisms scored are the presence versus absence of hybridisation to individual array elements. They reflect DNA sequence variation that determines which genomic sequences are present in the genomic representations.

Developing DArT^® for wheat and barley has been a two-step process. First, polymorphic markers were identified by screening libraries of random clones (“discovery arrays”). Second, polymorphic clones were assembled on a “typing array” for routine genotyping.

In principle, the markers could be located anywhere in the genome, and preferably should provide broad coverage. Our maps of DArT^® markers for barley (PNAS June 2004: www.pnas.org/cgi/content/abstract/0401076101v1 ) and wheat (Theoretical and Applied Genetics Vol 113, No.8, November 2006, DOI 10.1007/s00122-006-0365-4) confirm that this is the case. The latter paper describes a whole-genome integrated map for a cross between wheat cultivars Cranbrook and Halberd using 339 RFLP, SSR and AFLP markers, 71 STM markers and 339 DArT markers.

Please see also our alignment of the maps of 9 wheat crosses (Version 1.2, constructed February 2007). The Read Me document explains the content and rationale: this is a work in progress. For more information contact peter  DiversityArrays.com