Inheritance of the Isozyme Isocitrate Dehydrogenase (IDH) in a Natural Population of Polyploid White Clover (Trifolium Repens L.)

Abstract

An electrophoretic study of segregation of isocitrate dehydrogenase (IDH) was undertaken in polyploid white clover (Trifolium repem L.). The study aimed to test the conflicting theories on enzyme inheritance patterns in this species. A number of controlled selfings and reciprocal crosses were performed as well as a study of distribution of alleles in a natural Danish population of white clover. The result of the selfing experiment was that the chosen material is strongly self-incompatible, The offspring from the crosses showed that two isoloci were present and that the alleles in these segregate in a Mendelian fashion. Five different IDH-phenotypes, composed of two alleles, where found in the natural population. This contrasts with previous findings, for this and other allotetraploid species, of one variant and one invariant isolocus. Maximum likelihood analysis of the distribution of these phenotypes showed that the two alleles were equally common on an overall population basis. Each of these alleles were, however, most frequent in one of the isoloci. The findings reported here strongly support the theory that white clover is an allotetraploid, showing disomic inheritance.

Islands as refugia of Trifolium repens genetic diversity

“…It should be noted that these methods are designed for a maximum of two alleles per locus, and using them in a tetraploid species such as T. repens can lead to an overestimate of allele frequencies and an underestimate of within-population genetic diversity (Lynch and Milligan 1994;Krauss 2000). However, as T. repens is an allotetraploid and shows disomic inheritance (Caradus 1995;Weidema 1996), any such effects are of no concern.…”

Estimation of Preferential Pairing Rates in Second-Generation Autotetraploid Pacific Oysters (Crassostrea gigas)

“…Use of allozyme markers has revealed an increasing number of natural autopolyploids , many with tetrasomic inheritance and references therein; Maki et al 1996;Weidema 1996;Fjellstrom et al 2001). Many of these studies have focused on differentiating between the two extremes, disomic and tetrasomic inheritance (Rieseberg and Doyle 1989;Soltis and Soltis 1989;Maki et al 1996;Weidema 1996).…”

“…Use of allozyme markers has revealed an increasing number of natural autopolyploids , many with tetrasomic inheritance and references therein; Maki et al 1996;Weidema 1996;Fjellstrom et al 2001). Many of these studies have focused on differentiating between the two extremes, disomic and tetrasomic inheritance (Rieseberg and Doyle 1989;Soltis and Soltis 1989;Maki et al 1996;Weidema 1996). In reality, patterns of inheritance may be far more complex, as revealed by highly polymorphic molecular markers (Fjellstrom et al 2001), with divergence between chromosomes leading to a progression from tetrasomic to disomic inheritance at linked loci (Weiss and Maluszynska 2000).…”