Chromosomal and phylogenetic context for conglutin genes in Arachis based on genomic sequence

Mol Genet Genomics. 2006 Jun;275(6):578-92. doi: 10.1007/s00438-006-0114-z. Epub 2006 Apr 14.


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.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Arachis / genetics*
  • Base Sequence
  • Blotting, Southern
  • Chromosomes, Plant*
  • DNA, Plant
  • Genome, Plant*
  • In Situ Hybridization, Fluorescence
  • Molecular Sequence Data
  • Phylogeny*
  • Plant Proteins / genetics*
  • Sequence Homology, Nucleic Acid


  • DNA, Plant
  • Plant Proteins