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The following points highlight the three main importance of chromosomal aberrations. The importance are: 1. Role in Evolution 2. Role in Genetic Analysis 3. Role in Plant Breeding.
Chromosomal Aberrations: Importance # 1.Role in Evolution:
The study of the karyotypes of different species has revealed interesting facts about the plant kingdom. It has been demonstrated that individuals in wild populations are, to some extent, heterogeneous cytologically and genetically. In some cases, even if the genes are identical they may be ordered in a different way, owing to alterations of the chromosomal segments.
These changes have an important bearing on the evolution of species.
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Observation of chromosomal organization and of the different karyotypes in the individual, the species, genera, and the major systematic groups indicates that chromosomal aberration is involved in the process of evolution. One of the most frequent causes of evolution is a change in the order of genes as a result of chromosomal aberrations.
Thus chromosomal aberrations play a vital role in evolution as they generate variation in a natural population.
Natural selection maintains the polymorphism for gross chromosomal changes in plants like Oenothera, Datura, Rhoeo, Clarkia, Campanula, etc. Reciprocal translocations along with alternate chromosome segregation ensure the maintenance of heterozygosity and prevent the expression of lethal genes.
Duplications ensure the perpetuation of genes which are present in single dose. Inversions prevent pairing between homologous parts and suppress crossing over.
Chromosomal Aberrations: Importance # 2. Role in Genetic Analysis:
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Chromosomal aberrations have been very helpful in genetic analysis. Trans-located strains of maize were used to demonstrate that a cytological exchange of chromosome parts results into genetic recombination. In different crop species, translocations, duplications and deficiencies have been used in mapping of gene locus.
Chromosomal Aberrations: Importance # 3.Role in Plant Breeding:
Aberrations result in altered linkage relationships and this has been exploited for breeding experiments.
