Submitted to: Plant Genome Analysis Abstracts
Publication Type: Abstract Only
Publication Acceptance Date: 11/1/2004
Publication Date: 12/15/2004
Citation: Havey, M.J., Kuhl, J., Cheung, F., Yuan, Q., Martin, W.J., Zewdie, Y., Sink, K., Jenderek, M.M., Prince, J., Town, C. 2004. Genomic analyses and comparisons between the monocot orders asparagales and poales. Plant Genome Analysis Abstracts.
Technical Abstract: The class Commelinanae and order Asparagales are two sister monophyletic groups within the monocots. The order Poales of the class Commelinanae possesses the most economically important monocots; the Asparagales is the second most economically valuable monocot order and includes such important plants as agave, aloe, asparagus, garlic, iris, onion, orchid, and vanilla. Genomic analyses of the Asparagales are hampered by relatively long generation times and some of the largest nuclear genomes known among all eukaryotes. Onion (Allium cepa) is a diploid (2n=2x=16) with a nuclear genome of 16,415 megabasepairs per 1C, approximately equal to hexaploid wheat. Biochemical and FISH analyses revealed that the onion genome consists primarily of middle-repetitive sequences in short-period interspersions among single-copy regions. In order to assess genomic differences between the Asparagales and Poales, we generated 11,008 unique onion ESTs and undertook comparative mapping and sequence-based comparisons. Little synteny was revealed between onion and rice, at least at the recombinational level. Expressed sequence and genomic comparisons revealed strong differences between the Asparagales and Poales for mean GC content and distribution across coding regions, indicating that genomic characteristics are not uniform across the monocots. Research should now focus on identifying an appropriate genomic model for the huge-genome Asparagales.