DArT markers: diversity analyses, genomes comparison, mapping and integration with SSR markers in <it>Triticum monococcum</it>

• Main Authors: Huttner Eric, Wenzl Peter, Berry Simon, Kanyuka Kostya, Bayon Carlos, Jing Hai-Chun, Kilian Andrzej, E Hammond-Kosack Kim
• Format: Article
• Language: English
• Published: BMC 2009-09-01
• Series: BMC Genomics
• Online Access: http://www.biomedcentral.com/1471-2164/10/458

<p>Abstract</p> <p>Background</p> <p><it>Triticum monococcum </it>(2<it>n </it>= 2<it>x </it>= 14) is an ancient diploid wheat with many useful traits and is used as a model for wheat gene discovery. DArT (Diversity Arrays Technology) employs a hybridisation-based approach to type thousands of genomic loci in parallel. DArT markers were developed for <it>T. monococcum </it>to assess genetic diversity, compare relationships with hexaploid genomes, and construct a genetic linkage map integrating DArT and microsatellite markers.</p> <p>Results</p> <p>A DArT array, consisting of 2304 hexaploid wheat, 1536 tetraploid wheat, 1536 <it>T. monococcum </it>as well as 1536 <it>T. boeoticum </it>representative genomic clones, was used to fingerprint 16 <it>T. monococcum </it>accessions of diverse geographical origins. In total, 846 polymorphic DArT markers were identified, of which 317 were of <it>T. monococcum </it>origin, 246 of hexaploid, 157 of tetraploid, and 126 of <it>T. boeoticum </it>genomes. The fingerprinting data indicated that the geographic origin of <it>T. monococcum </it>accessions was partially correlated with their genetic variation. DArT markers could also well distinguish the genetic differences amongst a panel of 23 hexaploid wheat and nine <it>T. monococcum </it>genomes. For the first time, 274 DArT markers were integrated with 82 simple sequence repeat (SSR) and two morphological trait loci in a genetic map spanning 1062.72 cM in <it>T. monococcum</it>. Six chromosomes were represented by single linkage groups, and chromosome 4A^mwas formed by three linkage groups. The DArT and SSR genetic loci tended to form independent clusters along the chromosomes. Segregation distortion was observed for one third of the DArT loci. The <it>Ba </it>(black awn) locus was refined to a 23.2 cM region between the DArT marker locus <it>wPt-2584 </it>and the microsatellite locus <it>Xgwmd33 </it>on 1A^m; and the <it>Hl </it>(hairy leaf) locus to a 4.0 cM region between DArT loci <it>376589 </it>and <it>469591 </it>on 5A^m.</p> <p>Conclusion</p> <p>DArT is a rapid and efficient approach to develop many new molecular markers for genetic studies in <it>T. monococcum</it>. The constructed genetic linkage map will facilitate localisation and map-based cloning of genes of interest, comparative mapping as well as genome organisation and evolution studies between this ancient diploid species and other crops.</p>