The Organization and Rate of Evolution of Wheat Genomes Are Correlated With Recombination Rates Along Chromosome Arms
- Eduard D. Akhunov1,
- Andrew W. Goodyear1,
- Shu Geng1,
- Li-Li Qi2,
- Benjamin Echalier2,
- Bikram S. Gill2,
- Miftahudin3,
- J. Perry Gustafson4,
- Gerard Lazo5,
- Shiaoman Chao5,
- Olin D. Anderson5,
- Anna M. Linkiewicz1,
- Jorge Dubcovsky1,
- Mauricio La Rota6,
- Mark E. Sorrells6,
- Deshui Zhang7,
- Henry T. Nguyen3,
- Venugopal Kalavacharla8,
- Khwaja Hossain8,
- Shahryar F. Kianian8,
- Junhua Peng9,
- Nora L.V. Lapitan9,
- Jose L. Gonzalez-Hernandez10,
- James A. Anderson10,
- Dong-Woog Choi11,
- Timothy J. Close11,
- Muharrem Dilbirligi12,
- Kulvinder S. Gill12,
- M. Kay Walker-Simmons13,
- Camille Steber14,
- Patrick E. McGuire15,
- Calvin O. Qualset15, and
- Jan Dvorak1,16
- 1Department of Agronomy and Range Science, University of California, Davis, California 95616, USA; 2Department of Plant Pathology, Throckmorton Hall, Kansas State University, Manhattan, Kansas 66506, USA; 3Department of Agronomy, University of Missouri, Columbia, Missouri 65211, USA; 4USDA-ARS, University of Missouri, Columbia, Missouri 65211, USA; 5USDA/ARS Western Regional Research Center, Albany, California 94710, USA; 6Department of Plant Breeding, Cornell University, Ithaca, New York 14853, USA; 7Department of Plant and Soil Science, Texas Tech University, Lubbock, Texas 79409, USA; 8Department of Plant Sciences, Loftsgard Hall, North Dakota State University, Fargo, North Dakota 58105–5051, USA; 9Department of Soil and Crop Sciences, Colorado State University, Fort Collins, Colorado 80524, USA; 10Department of Agronomy and Plant Genetics, University of Minnesota, Twin Cities, St. Paul, Minnesota 55108–6026, USA; 11Department of Botany and Plant Science, University of California, Riverside, California 92521, USA; 12Department of Crop and Soil Sciences, Washington State University, Pullman, Washington 99164–6420, USA; 13USDA-ARS National Program Staff, Beltsville, Maryland 20705–5139, USA; 14USDA-ARS, Department of Crop and Soil Sciences, Washington State University, Pullman, Washington 99164–6420, USA; 15Genetic Resources Conservation Program, University of California, Davis, California 95616, USA.
Abstract
Genes detected by wheat expressed sequence tags (ESTs) were mapped into chromosome bins delineated by breakpoints of 159 overlapping deletions. These data were used to assess the organizational and evolutionary aspects of wheat genomes. Relative gene density and recombination rate increased with the relative distance of a bin from the centromere. Single-gene loci present once in the wheat genomes were found predominantly in the proximal, low-recombination regions, while multigene loci tended to be more frequent in distal, high-recombination regions. One-quarter of all gene motifs within wheat genomes were represented by two or more duplicated loci (paralogous sets). For 40 such sets, ancestral loci and loci derived from them by duplication were identified. Loci derived by duplication were most frequently located in distal, high-recombination chromosome regions whereas ancestral loci were most frequently located proximal to them. It is suggested that recombination has played a central role in the evolution of wheat genome structure and that gradients of recombination rates along chromosome arms promote more rapid rates of genome evolution in distal, high-recombination regions than in proximal, low-recombination regions.
Footnotes
-
↵16 Corresponding author.
-
E-MAIL jdvorak{at}ucdavis.edu; FAX (530) 752-4361.
-
Article and publication are at http://www.genome.org/cgi/doi/10.1101/gr.808603. Article published online before print in April 2003.
-
- Received September 16, 2002.
- Accepted February 18, 2003.
- Cold Spring Harbor Laboratory Press
