A glimpse into the impossible: chromosome based physical mapping of the giant bread wheat genome.
The construction of the first physical map of a hexaploid wheat chromosome, 3B (~1Gb), demonstrates that physical mapping in large, complex, and highly repetitive genomes can be performed successfully with a chromosome-based strategy. As part of the international effort to sequence the hexaploid bread wheat genome (Triticum aestivum L.), we constructed a BAC-based physical map of the largest chromosome, 3B (995 Mb, ~1/3 human genome). Using a chromosome-specific BAC library, we assembled 82 % of the chromosome into 1,036 contigs and anchored 65 percent with markers, providing a major resource for structural, functional, and comparative genomic studies as well as for the development of efficient molecular tools for breeders. This first physical map establishes a template for completing the remaining wheat chromosomes and demonstrates the feasibility of constructing physical maps in large, complex, polyploid genomes using a chromosome-based approach.
Etienne Paux, Pierre Sourdille, Jérôme Salse, Cyrille Saintenac, Frédéric Choulet, Philippe Leroy, Abraham Korol, Monika Michalak, Shahryar Kianian, Wolfgang Spielmeyer, Evans Lagudah, Daryl Somers, Andrzej Kilian, Michael Alaux, Sonia Vautrin, Hélène Bergès, Kellye Eversole, Rudi Appels, Jan Safar, Hana Simkova, Jaroslav Dolezel, Michel Bernard, Catherine Feuillet.