Molecular and Biochemical Characterization of Somaclonal Variation

Abstract

Somaclonal variation may result from a wide range of genetic changes (Phillips et al., 1994; Karp, 1991, 1995; Jain, 1996). Major chromosomal re-arrangements may occur during tissue culture of plant cells (Orton, 1980b; Lapitan et al., 1984). Chromosomal duplication and increase in ploidy are often reported. At the other extreme, single base or point mutations are a mininal type of genetic change that results in somaclonal variation. Transposable elements may also be the source of variation. Somaclonal variation in nuclear, chloroplast and mitochondrial genomes is possible and changes in more than one of these genomes or by more than one of these mechanisms may be found in any individual somaclone. Several mitochondrial genotypes may exist in equilibrium in plant cells, with the equilibrium being disrupted in cell culture resulting in the appearance of previously rare genotypes (Shirzadegan et al., 1991). Deverno (1995) reviewed somaclonal variation during somatic embryogenesis of woody plants and concluded that somaclonal variation was an important source of new traits for plant improvement especially for this type of plant (trees and other long-lived perenial species). However, somaclonal variation can also introduce unwanted variation in attempts to propagate plants clonally.KeywordsSomatic EmbryogenesisRestriction Fragment Length PolymorphismAmplify Fragment Length PolymorphismChloroplast GenomeSomaclonal VariationThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.