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United States Department of Agriculture

Agricultural Research Service


item Havey, Michael
item Leite, Daniela
item Mccallum, John

Submitted to: International Symposium on the Edible Alliaceae
Publication Type: Abstract Only
Publication Acceptance Date: 1/30/2001
Publication Date: N/A
Citation: N/A

Interpretive Summary:

Technical Abstract: Partial sequencing of cDNAs offer several advantages for genomic analyses, including expressed sequence tags (ESTs) for RFLP mapping, probes to screen YAC or BAC libraries to construct physical maps, and samples of the expressed genes at a particular stage of development, in a particular environment, or after a specific treatment. Large-scale sequencing projects are currently underway for numerous model and economically important species, including Arabidopsis, maize, and rice. To date, seedling cDNA libraries have been used as sources of probes to map RFLPs onion. Over 1000 cDNAs were evaluated to identify a set of 250 cDNAs revealing RFLPs among accessions of cultivated onion. We sequenced all 250 of these clones in the process of converting our RFLP markers to PCR-based systems. We completed homology comparisons for all 250 ESTs using the BLASTN, BLASTX, and FASTA algorithms. As observed in other plant systems, approximately 25 percent of these selected cDNA clones showed homology to prevalent transcripts, such as rubisco, chlorophyll AB binding proteins, ubiquitin, and elongation factors. The rest of the cDNAs were unique with no hits in the databases or showed significant homology to ESTs from other plants. Over the long term onion ESTs will aid in gene-discovery and mapping of onion.

Last Modified: 09/20/2017
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