GENETIC MAPPING OF EXPRESSED SEQUENCES IN ONION AND COMPARISONS WITH GARLIC AND RICE

Michael J. Havey, William Martin, John McCallum, Masayoshi Shigyo, Jernej Jakse, Joseph C. Kuhl, Yayeh Zewdie, Naoko Yamane, Maria Jenderek, James P. Prince, Kenneth C. Sink, and Christopher D. Town

USDA-ARS and University of Wisconsin, Department of Horticulture, 1575 Linden Drive, University of Wisconsin, Madison, WI 53706. Phone: 608-262-1830; Fax: 608-262-4743; Email: mjhavey@wisc.edu.

The Poales (includes the grasses) and Asparagales (includes the Alliums) are two closely related monocot orders. Extensive genetic-linkage conservation (colinearity) has been demonstrated among the cultivated grasses, which aids in the identification, mapping, and cloning of economically important traits from related plants. It is not known if plants in the Asparagales (such as onion and garlic) show colinearity with the grasses. To address this question, we developed PCR-based codominant genetic markers from expressed regions of the onion DNA showing significant similarities to single positions in the rice DNA. An onion-genetic map of 175+ markers was developed and map positions in onion were compared with physical locations in rice. Although colinearity was revealed between garlic and onion, there was little colinearity between onion and rice on the recombinational level. These results indicate that the grasses are not representative of all monocots and genomic resources must be independently developed for the Alliums.

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