title: Chromosomal and phylogenetic context for conglutin genes in Arachis based on genomic sequence.
abstract: Comparative genomic and cDNA sequence analysis of ara h 2, a major peanut allergen, and a related conglutin ara h 6 were performed in Arachis hypogaea L. and its putative progenitors, Arachis duranensis and Arachis ipaensis. The complete identity between sequences encoding Ara h 2 isoforms demonstrated that these are homeologous genes and represent orthologs from diploid ancestors. Three copies of ara h 6 were identified in A. hypogaea, one of them located in the A-genome and the other two in the B-genome. Expression analysis showed higher levels of ara h 2 transcripts compared with ara h 6. Dual-labeled genomic in situ hybridization permitted identification of two subgenomes, each of which contained one pair of ara h 2-ara h 6 signals localized by fluorescence in situ hybridization. Characterization of genomic clones showed close genetic linkage between Ara h 2.02 and one copy of ara h 6 in the B-genome. The physical linkage may have arisen by tandem duplication and divergence of an ancestral gene. A gene duplication event specific to the B-genome progenitor has resulted in ara h 6 paralogs. These data provide further evidence for progenitor relationships and genomic organization of the conglutin gene family in the genus Arachis and could contribute to the development of a hypoallergenic peanut.
authors.affiliation: Department of Horticulture, University of Georgia Tifton Campus, Tifton, GA, 31793, USA.
authors.forename: M Laura
authors.initials: ML
authors.lastname: Ramos
authors.forename: Geraldine
authors.initials: G
authors.lastname: Fleming
authors.forename: Ye
authors.initials: Y
authors.lastname: Chu
authors.forename: Yukio
authors.initials: Y
authors.lastname: Akiyama
authors.forename: Maria
authors.initials: M
authors.lastname: Gallo
authors.forename: Peggy
authors.initials: P
authors.lastname: Ozias-Akins
mesh_terms: D010367:Arachis / Q000235:genetics*; D001483:Base Sequence; D015139:Blotting, Southern; D032461:Chromosomes, Plant; D018744:DNA, Plant; D018745:Genome, Plant; D017404:In Situ Hybridization, Fluorescence; D008969:Molecular Sequence Data; D010802:Phylogeny; D010940:Plant Proteins / Q000235:genetics*; D012689:Sequence Homology, Nucleic Acid
chemical_list: D018744:DNA, Plant; D010940:Plant Proteins