• C. North
Part of the Science in Horticulture Series book series (SCHSA)


The structure of chromosomes and the genes they carry is very consistent otherwise there would not be continuity in inheritance. However, changes to chromosomes do occasionally occur. Sometimes individual genes change to give new alleles and there may be larger alterations in structure. Chromosomes may break and pieces may be lost (deletion), pieces may break off and be rejoined in the reverse order (inversion), or a portion of one chromosome may be transferred to another chromosome (translocation). The way such changes can take place and the pairing of altered chromosomes is illustrated in Figure 6.1. Inversions and translocations in which the positions of chromosome portions are altered, but in which the gene complement remains the same, can still have a heritable effect because the chemical compounds produced by genes to influence development interact with those of their neighbours. Linkages are also altered. These changes, whether they involve individual genes or whole chromosomes, introduce new heritable characters known as mutations. Many drastic chromosome mutations are lethal and the cells containing them cannot survive, but smaller changes often give the individuals carrying them an opportunity to compete with more normal progeny and sometimes to gain ascendency and to develop as new forms better adapted to the environment.


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  1. d’AMATO, F. and HOFFMANN-OSTENHOF, O. (1956). Metabolism and spontaneous mutations in plants, Adv. Genet., 8, 1–28CrossRefGoogle Scholar
  2. BAUER, R. (1974). Westra, an X-ray induced erect-growing black currant variety, and its use in breeding, in Polyploidy and Induced Mutation, International Atomic Energy Agency, Vienna, 13–20Google Scholar
  3. BROERTJES, C. (1966). Mutation breeding of chrysanthemums, Euphytica, 15, 156–162Google Scholar
  4. BROERTJES, C., HACCIUS, B., and WEIDLICH, S. (1968). Adventitious bud formation on isolated leaves and its significance for mutation breeding, Euphytica, 17, 321–344Google Scholar
  5. BROERTJES, C. (1976). Mutation breeding in vegetatively propagated floricultural crops, Acta. hort., 63, 187–195Google Scholar
  6. BISHOP, C. J. (1959). Radiation-induced fruit colour mutants in apples, Can. J. Gen. Cyt., 1, 118–123CrossRefGoogle Scholar
  7. CATCHESIDE, D. G. (1948). Genetic effects of radiations, Adv. Genet., 2, 271–358CrossRefGoogle Scholar
  8. JENNINGS, D. L. (1961). Mutation for larger fruit in the raspberry, Nature, Lond., 191, 302–303CrossRefGoogle Scholar
  9. MULLER, H. J. (1927). Artificial transmutation of the gene, Science, 66, 84–87Google Scholar
  10. VISSER, T., VERHAEGH, J. J. and de VRIES, D. P. (1971). Pre-selection of com-pact mutants induced by X-ray treatment in apple and pear, Euphytica, 20, 153–207Google Scholar
  11. HAGBERG, A. and ÅKERBERG, E. (1962). Mutations and Polyploidy in Plant Breeding, Heinemann, London, 149 ppGoogle Scholar

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© C. North 1979

Authors and Affiliations

  • C. North
    • 1
  1. 1.Scottish Horticultural Research InstituteInvergowrie, DundeeScotland

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