An interchromosomal gene conversion of the Drosophila dunce locus identified with restriction site polymorphisms: A potential involvement of transposable elements in gene conversion

1987 ◽  
Vol 208 (1-2) ◽  
pp. 315-324 ◽  
Author(s):  
Steven J. Pittler ◽  
Helen K. Salz ◽  
Ronald L. Davis
1992 ◽  
Vol 12 (4) ◽  
pp. 1546-1552
Author(s):  
R J Bollag ◽  
D R Elwood ◽  
E D Tobin ◽  
A R Godwin ◽  
R M Liskay

We have studied intrachromosomal gene conversion in mouse Ltk- cells with a substrate designed to provide genetic evidence for heteroduplex DNA. Our recombination substrate consists of two defective chicken thymidine kinase genes arranged so as to favor the selection of gene conversion products. The gene intended to serve as the recipient in gene conversion differs from the donor sequence by virtue of a palindromic insertion that creates silent restriction site polymorphisms between the two genes. While selection for gene conversion at a XhoI linker insertion within the recipient gene results in coconversion of the nearby palindromic site in more than half of the convertants, 4% of convertant colonies show both parental and nonparental genotypes at the polymorphic site. We consider these mixed colonies to be the result of genotypic sectoring and interpret this sectoring to be a consequence of unrepaired heteroduplex DNA at the polymorphic palindromic site. DNA replication through the heteroduplex recombination intermediate generates genetically distinct daughter cells that comprise a single colony. We believe that the data provide the first compelling genetic evidence for the presence of heteroduplex DNA during chromosomal gene conversion in mammalian cells.


Genetics ◽  
1990 ◽  
Vol 126 (4) ◽  
pp. 813-822 ◽  
Author(s):  
N P Schultes ◽  
J W Szostak

Abstract We have constructed eight restriction site polymorphisms in the DED81-ARG4 region and examined their behavior during meiotic recombination. Tetrad analysis reveals decreasing gradients of gene conversion on both sides of the initiation site for meiotic recombination at the ARG4 locus, extending on one side into the ARG4 gene, and on the other side into the adjacent DED81 gene. Gene conversion events can extend in both directions from the initiation site as the result of a single meiotic event. There is a second gradient of gene conversion in DED81, with high levels near the 5' end of the gene and low levels near the middle of the gene. The peaks of gene conversion activity for the DED81 and ARG4 gradients map to regions where double-strand breaks are found during meiosis. The implications of these results for models of meiotic gene conversion are discussed.


1992 ◽  
Vol 12 (4) ◽  
pp. 1546-1552 ◽  
Author(s):  
R J Bollag ◽  
D R Elwood ◽  
E D Tobin ◽  
A R Godwin ◽  
R M Liskay

We have studied intrachromosomal gene conversion in mouse Ltk- cells with a substrate designed to provide genetic evidence for heteroduplex DNA. Our recombination substrate consists of two defective chicken thymidine kinase genes arranged so as to favor the selection of gene conversion products. The gene intended to serve as the recipient in gene conversion differs from the donor sequence by virtue of a palindromic insertion that creates silent restriction site polymorphisms between the two genes. While selection for gene conversion at a XhoI linker insertion within the recipient gene results in coconversion of the nearby palindromic site in more than half of the convertants, 4% of convertant colonies show both parental and nonparental genotypes at the polymorphic site. We consider these mixed colonies to be the result of genotypic sectoring and interpret this sectoring to be a consequence of unrepaired heteroduplex DNA at the polymorphic palindromic site. DNA replication through the heteroduplex recombination intermediate generates genetically distinct daughter cells that comprise a single colony. We believe that the data provide the first compelling genetic evidence for the presence of heteroduplex DNA during chromosomal gene conversion in mammalian cells.


1993 ◽  
Vol 111 (2-3) ◽  
pp. 239-243 ◽  
Author(s):  
David Ralph ◽  
Daniele Postic ◽  
Guy Baranton ◽  
Charles Pretzman ◽  
Michael McClelland

1988 ◽  
Vol 8 (2) ◽  
pp. 595-604
Author(s):  
L S Symington ◽  
T D Petes

To examine the relationship between genetic and physical chromosome maps, we constructed a diploid strain of the yeast Saccharomyces cerevisiae heterozygous for 12 restriction site mutations within a 23-kilobase (5-centimorgan) interval of chromosome III. Crossovers were not uniformly distributed along the chromosome, one interval containing significantly more and one interval significantly fewer crossovers than expected. One-third of these crossovers occurred within 6 kilobases of the centromere. Approximately half of the exchanges were associated with gene conversion events. The minimum length of gene conversion tracts varied from 4 base pairs to more than 12 kilobases, and these tracts were nonuniformly distributed along the chromosome. We conclude that the chromosomal sequence or structure has a dramatic effect on meiotic recombination.


1982 ◽  
Vol 2 (1) ◽  
pp. 30-41
Author(s):  
N A Oliver ◽  
D C Wallace

Two mitochondrially synthesized marker polypeptides, MV-1 and MV-2, were found in human HeLa and HT1080 cells. These were assigned to the mitochondrial DNA in HeLa-HT1080 cybrids and hybrids by demonstrating their linkage to cytoplasmic genetic markers. These markers include mitochondrial DNA restriction site polymorphisms and resistance to chloramphenicol, an inhibitor of mitochondrial protein synthesis. In the absence of chloramphenicol, the expression of MV-1 and MV-2 in cybrids and hybrids was found to be directly proportional to the ratio of the parental mitochondrial DNAs. In the presence of chloramphenicol, the marker polypeptide linked to the chloramphenicol-sensitive mitochondrial DNA continued to be expressed. This demonstrated that resistant and sensitive mitochondrial DNAs can cooperate within a cell for gene expression and that the CAP-resistant allele was dominant or codominant to sensitive. Such cooperation suggests that mitochondrial DNAs can be exchanged between mitochondria.


1988 ◽  
Vol 8 (7) ◽  
pp. 2942-2954
Author(s):  
M Kupiec ◽  
T D Petes

We have measured the frequency of meiotic recombination between marked Ty elements in the Saccharomyces cerevisiae genome. These recombination events were usually nonreciprocal (gene conversions) and sometimes involved nonhomologous chromosomes. The frequency of ectopic gene conversion among Ty elements appeared lower than expected on the basis of previous studies of recombination between artificially constructed repeats. The conversion events involved either a subset of the total Ty elements in the genome or the conversion tract was restricted to a small region of the Ty element. In addition, the observed conversion events were very infrequently associated with reciprocal exchange.


1984 ◽  
Vol 4 (5) ◽  
pp. 978-981 ◽  
Author(s):  
C Blatt ◽  
M E Harper ◽  
G Franchini ◽  
M N Nesbitt ◽  
M I Simon

The murine homologs of two viral oncogenes associated with tyrosine-specific kinase activity have been assigned to different loci in the mouse genome. The segregation of restriction site polymorphisms, as detected by probes that are specific for endogenous c-fes and c-src sequences, was followed in the DNA of recombinant inbred strains. The c-fes gene was mapped to the proximal portion of chromosome 7, very close to the Gpi-1 locus, whereas c-src was linked to the Psp locus on the distal half of chromosome 2.


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