Genomic relationships between the cultivated peanut (Arachis hypogaea, Leguminosae) and its close relatives revealed by double GISH

Arachis hypogaea is a natural, well-established allotetraploid (AABB) with 2n = 40. However, researchers disagree on the diploid genome donor species and on whether peanut originated by a single or multiple events of polyploidization. Here we provide evidence on the genetic origin of peanut and on t...

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Bibliographic Details
Published in:American journal of botany 2007-12, Vol.94 (12), p.1963-1971
Main Authors: Seijo, Guillermo, Lavia, Graciela I, Fernández, Aveliano, Krapovickas, Antonio, Ducasse, Daniel A, Bertioli, David J, Moscone, Eduardo A
Format: Article
Language:English
Subjects:
allopolyploidy
Arachis
Arachis hypogaea
Botany
Chromosomes
Diploidy
DNA
DNA probes
Flowers & plants
Genetic hybridization
Genetics
genome constitution
Genomes
Genomics
GISH
heterochromatin
peanut origin
Peanuts
Plant populations
Plants
Tetraploidy
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Summary:Arachis hypogaea is a natural, well-established allotetraploid (AABB) with 2n = 40. However, researchers disagree on the diploid genome donor species and on whether peanut originated by a single or multiple events of polyploidization. Here we provide evidence on the genetic origin of peanut and on the involved wild relatives using double GISH (genomic in situ hybridization). Seven wild diploid species (2n = 20), harboring either the A or B genome, were tested. Of all genomic DNA probe combinations assayed, A. duranensis (A genome) and A. ipaensis (B genome) appeared to be the best candidates for the genome donors because they yielded the most intense and uniform hybridization pattern when tested against the corresponding chromosome subsets of A. hypogaea. A similar GISH pattern was observed for all varieties of the cultigen and also for A. monticola. These results suggest that all presently known subspecies and varieties of A. hypogaea have arisen from a unique allotetraploid plant population, or alternatively, from different allotetraploid populations that originated from the same two diploid species. Furthermore, the bulk of the data demonstrated a close genomic relationship between both tetraploids and strongly supports the hypothesis that A. monticola is the immediate wild antecessor of A. hypogaea.
ISSN:0002-9122
1537-2197
DOI:10.3732/ajb.94.12.1963