ISSN:
1617-4623
Keywords:
Transposable elements
;
Mutation
;
Mutator
;
Maize
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Summary The mutagenic activity of the maize transposable element system Mutator can be lost by outcrossing to standard, non-Mutator lines or by repetitive intercrossing of genetically diverse Mutator lines. Lines losing Mutator mutagenic activity in either manner retain high copy numbers (10–15 per diploid genome) of the Mutator-associated Mu transposable elements. Frequent transposition of Mu1-related elements is observed only in active Mutator lines, however. The loss of Mutator activity on intercrossing is correlated with an increase in the copy number of Mu1-like elements to 40–50 per diploid genome, implying a self-encoded or self-activated negative regulator of Mu1 transposition. The outcross loss of Mutator activity is only weakly correlated with a low Mu element copy number and may be due to the loss of a positive regulatory factor encoded by a subset of Mu1-like elements. Transposition of Mu elements in active Mutator lines generates multiple new genomic positions for about half the elements each plant generation. The appearance of Mu1-like elements in these new positions is not accompanied by equally high germinal reversion frequencies, suggesting that Mu1 may commonly transpose via a DNA replicative process.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00330422
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