Basis for the diversity of states of controlling elements in maize

Petérson, Peter A.

doi:10.1007/bf00275956

Cited by 47 publications

(26 citation statements)

References 55 publications

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“…In S. fimicola, the range of variation of the Rec+ effect was not limited only to the degree of conversion suppression, but in some cases the Rec+ factor behaved as a conversion enhancer. Such enhancing factors are known in Zea (Peterson 1960), Saccharomyces (Maloney and Fogel 1980;Boram and Roman 1976) and Neurospora (Golin and Esposito 1977). Dose effect of Reck was observed in the present study, and the same was reported in Ustilago (Holliday et a1.1976).…”

Section: Conversion Frequencies and Composition Of Locisupporting

confidence: 89%

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Characteristics of gene conversion and Rec factor of the i locus of Sordaria fimicola.

Kitani

1982

The Japanese journal of genetics

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Apart from the previously studied g-locus, the i-locus showed the following characteristics.I. One-point cross conversion frequencies were roughly constant around 10 x 10-3, unless associated with a Rec+ factor. II. The interallelic conversion frequencies were either the sum of parental one-point cross conversion frequencies (20 X 10-3) or still higher than this, suggesting that this locus has compound composition with at least two units. III. Whenever interallelic cross conversion frequency was notably higher than 20 x 10-3, the ascus frequency of the spore colour ratio, 2+, 2i, 4b (asci of this composition can be developed through gene conversion or appear as tetratypes through reciprocal recombination) was high enough to include the excess portion of the conversion frequency, leaving substantial surplus. This suggests that the i-locus is composed of multiple units, and at the joints of units ordinary reciprocal cross-overs occur producing tetratype asci; and cosequently raising the apparent conversion frequencies. IV. The original blur allele was accompanied with a Rec+ factor, and therefore, its conversion frequency was low. Through gene conversion, this factor was removed from bins and transferred to the wild type allele. V. The Rec factor functions as a mutator on the alleles in the i-locus, and by itself, it was labile. Among the above characteristics, III and V respectively show close relationships with the compound genes of Neurospora and the mutable genes of Zea.

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Section: Conversion Frequencies and Composition Of Locisupporting

confidence: 89%

“…The mutable genes and the accompanied modulating factors in Zea mat's also do the same (McClintock 1956;Brink and Williams 1973;Peterson 1976;Freeling 1978).…”

Section: Conversion Frequencies and Composition Of Locimentioning

confidence: 89%

Characteristics of gene conversion and Rec factor of the i locus of Sordaria fimicola.

Kitani

1982

The Japanese journal of genetics

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“…She designated the new unstable alleles that arose in this manner "changes in state" (8, 9). Since then, derivatives of this kind have been identified by a number of investigators from a variety of insertion mutations (10)(11)(12)(13)(14)(15)(16). In addition to changes in the frequency and timing of somatic reversion, these derivatives can involve alterations in the basal level of expression of the affected gene (9, 10, 16) and differences in the rate ofgerminal change (10,12,15).…”

Section: Introductionmentioning

confidence: 99%

“…Since then, derivatives of this kind have been identified by a number of investigators from a variety of insertion mutations (10)(11)(12)(13)(14)(15)(16). In addition to changes in the frequency and timing of somatic reversion, these derivatives can involve alterations in the basal level of expression of the affected gene (9, 10, 16) and differences in the rate ofgerminal change (10,12,15).Two main hypotheses have been proposed to explain the molecular basis for changes in state of unstable mutations. The composition hypothesis (2, 17) postulates that these derivatives are due to changes within the element, whereas the position hypothesis (12) maintains that the element is unaltered but resides in a different location within the affected gene.…”

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confidence: 99%

Deletions within a defective suppressor-mutator element in maize affect the frequency and developmental timing of its excision from the bronze locus.

Schiefelbein

Raboy²,

Fedoroff³

et al. 1985

Proc. Natl. Acad. Sci. U.S.A.

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Six independent derivatives of the bz-ml3 allele, which contains a 2.2-kilobase-pair defective Suppressormutator (dSpm) insertion at the bronze (bz) locus, have been isolated and analyzed. The derivatives were selected for alterations in the frequency and timing of somatic reversion; such derivatives have previously been analyzed genetically and designated "changes in state" by McClintock [McClintock, B. (1955) Carnegie Inst. Washington, Yearb. 54, 245-255]. All of the derivatives analyzed in the present study revert substantially later in development than the original insertion mutation and some show a very low frequency of reversion as well. All of the derivatives contain insertions at the same site as the parent bz-m13 allele. Deletions of 400-1300 base pairs were found in the dSpm elements in four of the six derivatives; the remaining derivatives could not be distinguished structurally from the original mutant allele. The results suggest that changes in the frequency and developmental timing of excision are attributable to alterations in the dSpm element. Furthermore, these data suggest that DNA sequences near the ends of the element are important for responding to the two transacting functions supplied by the transposition-competent Suppressor-mutator (Spm) element.Transposable elements were first identified and described in maize (1, 2). Early work revealed the presence of distinct families of elements, each composed of members able to transpose on their own (transposition-competent elements) and members unable to transpose in the absence of a transposition-competent member (defective elements; for reviews see refs. 3 and 4). Recent molecular analyses of maize transposable elements have shown that the defective elements of a family are often deletion derivatives of the transposition-competent elements (5-7).Mutations caused by the insertion of transposition-competent elements in or near a locus are unstable, reverting both somatically and germinally at a high frequency. Mutations caused by insertions of defective elements are unstable only when a transposition-competent element of the same family is present in the genome. A characteristic of each unstable mutation is its particular pattern of somatic reversion. McClintock described the isolation of derivatives of insertion mutations that showed heritable changes in the frequency and developmental timing of somatic reversion. She designated the new unstable alleles that arose in this manner "changes in state" (8, 9). Since then, derivatives of this kind have been identified by a number of investigators from a variety of insertion mutations (10)(11)(12)(13)(14)(15)(16). In addition to changes in the frequency and timing of somatic reversion, these derivatives can involve alterations in the basal level of expression of the affected gene (9, 10, 16) and differences in the rate ofgerminal change (10,12,15).Two main hypotheses have been proposed to explain the molecular basis for changes in state of unstable mutations. The composition hypothesis (2, 17...

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“…As with the Ac-Ds system, the states of receptor and regulatory elements in Spm(En) system will be discussed respectively. The cyclic changes of controlling element phasic activity have also been described for the ^ element (Peterson, 1965b(Peterson, , 1966 A. SH…”

Section: Transposition Of Transposable Elements In Maizementioning

confidence: 92%

Genetic analysis of the behavior of a multiple gene loss induced by a transposon in maize

Huang

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INFORMATION TO USERSThis was produced from a copy of a document sent to us for microfilming. While the most advanced technological means to photograph and reproduce this document have been used, the quality is heavily dependent upon the quality of the material submitted.The following explanation of techniques is provided to help you understand markings or notations which may appear on this reproduction. 1. The sign or "target" for pages apparently lacking from the document photographed is "Missing Page(s)". If it was possible to obtain the missing page(s) or section, they are spliced into the film along with adjacent pages. This may have necessitated cutting through an image and duplicating adjacent pages to assure you of complete continuity. When an image on the film is obliterated with a round black mark it is anindication that the fîlm inspector noticed either blurred copy because of movement during exposure, or duplicate copy. Unless we meant to delete copyrighted materials that should not have been filmed, you will find a good image of the page in the adjacent frame.3. When a map, drawing or chart, etc., is part of the material being photo graphed the photographer has followed a definite method in "sectioning" the material. It is customary to begin filming at the upper left hand comer of a large sheet and to continue from left to right in equal sections with small overlaps. If necessary, sectioning is continued again-beginning below the first row and continuing on until complete.4. For any illustrations that cannot be reproduced satisfactorily by xerography, photographic prints can be purchased at additional cost and tipped into your xerographic copy. Requests can be made to our Dissertations Customer Services Department.5. Some pages in any document may have indistinct print. In all cases we have filmed the best available copy. Signature was redacted for privacy. University Mlcrdfilms InternationalSignature was redacted for privacy.Signature was redacted for privacy.ii Consequently, a mutation caused by insertion of Ds is unstable only in the presence of In the subsequent discussion, these properties will be described in detail under separate subjects.Like the Ac-Ds system, the Spm(En) system contains regulatory and receptor elements. The regulatory element of this system was designated Suppresscr-mutator (Spm) by McClintock (1954) and Enhancer (En) by Peterson (1953a). The receptor element was not named by McClintock and was termed Inhibitor (I) by Peterson (1953a) . The Spm and jto elementswere identified as members of the same system through the activation cri These interactions between two elements and the action of Spm (En) will be discussed in subsequent sections. Chromosome Rearrangements General mechanisms of chromosome rearrangementIn the early studies, McClintock ( Transposition of Transposable Elements in MaizeIn a previous section a general overview about the interaction of regulatory and receptor elements in two-element systems has been presented (Section 2.1). The receptor element is prese...

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Basis for the diversity of states of controlling elements in maize

Cited by 47 publications

References 55 publications

Characteristics of gene conversion and Rec factor of the i locus of Sordaria fimicola.

Characteristics of gene conversion and Rec factor of the i locus of Sordaria fimicola.

Deletions within a defective suppressor-mutator element in maize affect the frequency and developmental timing of its excision from the bronze locus.

Genetic analysis of the behavior of a multiple gene loss induced by a transposon in maize

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