As pointed out in the introduction, the process of cell division in higher eukaryotes appears to be naturally error-prone. It has been argued that differences in overt manifestations of somaclonal variation, which emanate from such errors, are a function of intrinsic selective forces, possibly in combination with altered mistake rates (Orton, 1983). For example, a broader range of variant cells would be expected to remain viable in the context of a suspension culture as compared to a highly differentiated plant structure. In addition, there is a strong suggestion that somaclonal variation is mediated or conditioned at least in part by genotype. Other factors that bear on somaclonal variation, such as age, transfer technique, and medium composition, are probably manifestations of selection (or possibly mutagenic activity as in the case of 2,4-D). More research incorporating improved designs and utilizing new techniques to visualize variability will be needed to elucidate the precise roles that selection and mutation play in the generation of genetic variability in somatic tissues. This knowledge should provide a basis for the design of propagation protocols to minimize or directionally maximize its expression.
All Science Journal Classification (ASJC) codes
- Molecular Biology
- Plant Science