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Location: Vegetable Crops Research

Title: Sequencing and mapping of the onion genome

item Havey, Michael
item Bohanec, Borut

Submitted to: National Allium Research Conference
Publication Type: Abstract Only
Publication Acceptance Date: 12/2/2010
Publication Date: 12/8/2010
Citation: Havey, M.J., Bohanec, B. 2010. Sequencing and mapping of the onion genome [abstract]. National Allium Research Conference. Paper No. O-01.

Interpretive Summary:

Technical Abstract: The cost of DNA sequencing continues to decline and, in the near future, it will become reasonable to undertake sequencing of the enormous nuclear genome of onion. We undertook sequencing of expressed and genomic regions of the onion genome to learn about the structure of the onion genome, as well as the best approach for deep coverage sequencing. As expected, pilot sequencing of onion genomic BACs revealed very low gene densities. However sequencing of random onion genomic clones after methyl filtration substantially increased hits to genic regions. These results indicate that sequencing of onion DNA should concentrate on expressed regions and reduced representation libraries to assemble a unigene set for onion and reveal SNPs for high throughput genotyping and molecular-aided selection. Mapping of SNPs will be done using a new haploid mapping family of onion. 5225 is a red, doubled-haploid onion and was kindly provided by Seminis Seed Company. OH-1 is a yellow synthetic population that shows high frequencies of gynogenic haploid production. Individual plants of OH-1 and 5225 were crossed and seed was harvested from the OH-1 parent. From one cross, red bulbs were selected as hybrids and sent to Slovenia for haploid extractions. Highly pure DNA has been isolated from the haploids for mapping. These haploids have also been asexually propagated and will be used for genetic analyses of bulb-quality traits. A Collection of Historical Photos from US Onion Breeding and Pathology.