Large-scale chromosomal restructuring is induced by the transposable element tam3 at the nivea locus of antirrhinum majus.
The transposable element, Tam3, gives rise to large-scale (greater than 1 kb) chromosomal rearrangements at a low frequency, when it is inserted at the nivea locus of Antirrhinum majus. Although some deletions may result from imprecise excision of Tam3, rearrangements involving deletion, dispersion and inverted duplication of flanking sequences, where Tam3 remains in situ, have also been identified. These rearrangements have been mapped at the molecular level, and the behavior of Tam3 following rearrangement has been observed. It is clear that Tam3 has enormous potential to restructure chromosomes through successive rounds of large-scale rearrangements. The mechanisms by which such rearrangements might arise are discussed.
Martin
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Department of Genetics, John Innes Institute, Norwich NR4 7UH, England.
Mackay
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Carpenter
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