Use of single-primer DNA amplifications in genetic studies of peanut (Arachis hypogaea L.)

Abstract

A recent approach to detecting genetic polymorphism involves the amplification of genomic DNA using single primers of arbitrary sequence. When separated electrophoretically in agarose gels, the amplification products give banding patterns that can be scored for genetic variation. The objective of this research was to apply these techniques to cultivated peanut (Arachis hypogaea L.) and related wild species to determine whether such an approach would be feasible for the construction of a genetic linkage map in peanut or for systematic studies of the genus. Two peanut cultivars, 25 unadapted germplasm lines of A. hypogaea, the wild allotetraploid progenitor of cultivated peanut (A. monticola), A. glabrata (a tetraploid species from section Rhizomatosae), and 29 diploid wild species of Arachis were evaluated for variability using primers of arbitrary sequence to amplify segments of genomic DNA. No variation in banding pattern was observed among the cultivars and germplasm lines of A. hypogaea, whereas the wild Arachis species were uniquely identified with most primers tested. Bands were scored (+/-) in the wild species and the PAUP computer program for phylogenetic analysis and the HyperRFLP program for genetic distance analysis were used to generate dendrograms showing genetic relationships among the diploid Arachis species evaluated. The two analyses produced nearly identical dendrograms of species relationships. In addition, approximately 100 F2 progeny from each of two interspecific crosses were evaluated for segregation of banding patterns. Although normal segregation was observed among the F2 progeny from both crosses, banding patterns were quite complex and undesirable for use in genetic mapping. The dominant behavior of the markers prevented the differentiation of heterozygotes from homozygotes with certainty, limiting the usefulness of arbitrary primer amplification products as markers in the construction of a genetic linkage map in peanut.

Rapid detection of genetic variability in chrysanthemum (Dendranthema grandiflora Tzvelev) using random primers

“…In Louisiana irises variation within species was low and natural hybrids among the species were identified because they possessed fragments of both species (Arnold eta!., 1991). In Arachis species dendrograms were generated using RAPD fragments as characters (Halward et al, 1992). These dendrograms showed relationships among Arachis species that were in concordance with species relationships derived from allozymes, RFLPs and morphological characters.…”

The genome sequences of Arachis duranensis and Arachis ipaensis, the diploid ancestors of cultivated peanut

“…The Arachis genus is endemic to South America and is composed mostly of diploid species (2n = 2x = 20). A. hypogaea is an allotetraploid (AABB-type genome; 2n = 4x = 40), probably derived from a single recent hybridization event between two diploid species and polyploidization [1][2][3][4][5][6] . Chromosomes are of mostly similar size and are metacentric, but strong chromosomal centromeric banding and one pair of small chromosomes distinguish the A from the B subgenome.…”

Genetic relationships among Arachis species based on AFLP

“…The phylogenetic relationships in the genus Arachis have also been studied using different molecular markers, such as seed protein profiles (Singh et al, 1991;Singh et al, 1994), isoenzymes (Stalker et al, 1994;Maass and Ocampo, 1995;Galgaro et al, 1997), RAPDs (Halward et al, , 1992Gimenes et al, 2000), and RFLPs Paik-Ro et al, 1992;Stalker et al, 1995;Kochert et al, 1996, Galgaro et al, 1998. All those markers have generated information that has been very useful for solving taxonomic and phylogenetic questions in this genus.…”