scholarly journals Isolation of the Drosophila melanogaster dunce chromosomal region and recombinational mapping of dunce sequences with restriction site polymorphisms as genetic markers.

1984 ◽  
Vol 4 (2) ◽  
pp. 358-367 ◽  
Author(s):  
R L Davis ◽  
N Davidson
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Meiotic Recombination ◽  
Restriction Site ◽  
Chromosomal Region ◽  
Nucleotide Metabolism ◽  
X Chromosomes ◽  
Chromosomal Walking ◽  
Chromosome Bands ◽  
Restriction Site Polymorphisms

Using the method of chromosomal walking, we have isolated a contiguous region of the Drosophila melanogaster X chromosome which corresponds to salivary gland chromosome bands 3C12 to 3D4. This five-band region contains approximately 100 kilobases of DNA, including those sequences comprising dunce, a gene which functions in memory and cyclic nucleotide metabolism. Genome blots of DNA from flies carrying several different chromosomal aberrations with breakpoints in the region have been probed with the isolated clones to map the breakpoints on the cloned DNA and to delimit dunce sequences. This has localized dunce to a 50-kilobase region. In addition, we have searched this 50-kilobase region for restriction site polymorphisms between X chromosomes from different Drosophila strains by genome blotting experiments, and we have followed the segregation of detected polymorphisms and dunce alleles after meiotic recombination. The data map one dunce mutation between two polymorphisms located 10 to 12 kilobases apart.

scholarly journals Isolation of the Drosophila melanogaster dunce chromosomal region and recombinational mapping of dunce sequences with restriction site polymorphisms as genetic markers

1984 ◽  
Vol 4 (2) ◽  
pp. 358-367
Author(s):  
R L Davis ◽  
N Davidson
Keyword(s):  
Drosophila Melanogaster ◽  
Salivary Gland ◽  
Meiotic Recombination ◽  
Restriction Site ◽  
Chromosomal Region ◽  
Nucleotide Metabolism ◽  
X Chromosomes ◽  
Chromosomal Walking ◽  
Chromosome Bands ◽  
Restriction Site Polymorphisms

Using the method of chromosomal walking, we have isolated a contiguous region of the Drosophila melanogaster X chromosome which corresponds to salivary gland chromosome bands 3C12 to 3D4. This five-band region contains approximately 100 kilobases of DNA, including those sequences comprising dunce, a gene which functions in memory and cyclic nucleotide metabolism. Genome blots of DNA from flies carrying several different chromosomal aberrations with breakpoints in the region have been probed with the isolated clones to map the breakpoints on the cloned DNA and to delimit dunce sequences. This has localized dunce to a 50-kilobase region. In addition, we have searched this 50-kilobase region for restriction site polymorphisms between X chromosomes from different Drosophila strains by genome blotting experiments, and we have followed the segregation of detected polymorphisms and dunce alleles after meiotic recombination. The data map one dunce mutation between two polymorphisms located 10 to 12 kilobases apart.

scholarly journals Recombination can initiate and terminate at a large number of sites within the rosy locus of Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 118 (2) ◽  
pp. 261-266
Author(s):  
S H Clark ◽  
A J Hilliker ◽  
A Chovnick
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Markers ◽  
Restriction Site ◽  
Intragenic Recombination ◽  
Dna Homology ◽  
Coding Region ◽  
Heterozygous Genotype ◽  
Order Of Magnitude ◽  
Dna Restriction ◽  
Restriction Site Polymorphisms

Abstract This report presents the results of a recombination experiment designed to question the existence of special sites for the initiation or termination of a recombination heteroduplex within the region of the rosy locus. Intragenic recombination events were monitored between two physically separated rosy mutant alleles ry301 and ry2 utilizing DNA restriction site polymorphisms as genetic markers. Both ry301 and ry2 are known from previous studies to be associated with gene conversion frequencies an order of magnitude lower than single site mutations. The mutations are associated with large, well defined insertions located as internal sites within the locus in prior intragenic mapping studies. On the molecular map, they represent large insertions approximately 2.7 kb apart in the second and third exons, respectively, of the XDH coding region. The present study monitors intragenic recombination in a mutant heterozygous genotype in which DNA homology is disrupted by these large discontinuities, greater than the region of DNA homology and flanking both sides of the locus. If initiation/or termination requires separate sites at either end of the locus, then intragenic recombination within the rosy locus of the heterozygote should be eliminated. Contrary to expectation, significant recombination between these sites is seen.

scholarly journals Decreasing gradients of gene conversion on both sides of the initiation site for meiotic recombination at the ARG4 locus in yeast.

Genetics ◽  
1990 ◽  
Vol 126 (4) ◽  
pp. 813-822 ◽  
Author(s):  
N P Schultes ◽  
J W Szostak
Keyword(s):  
Gene Conversion ◽  
Meiotic Recombination ◽  
Restriction Site ◽  
Initiation Site ◽  
Double Strand Breaks ◽  
Tetrad Analysis ◽  
Strand Breaks ◽  
Second Gradient ◽  
Low Levels ◽  
Restriction Site Polymorphisms

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.

scholarly journals Restriction map variation at the adh locus of Drosophila melanogaster in inverted and noninverted chromosomes.

Genetics ◽  
1988 ◽  
Vol 119 (1) ◽  
pp. 135-140
Author(s):  
M Aguade
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Population ◽  
Evolutionary History ◽  
Restriction Site ◽  
Restriction Enzymes ◽  
Restriction Map ◽  
Allozyme Polymorphism ◽  
Length Polymorphisms ◽  
History Of ◽  
Restriction Site Polymorphisms

Abstract Restriction map variation among 39 Standard and 40 In(2L)t chromosomes extracted from a Spanish natural population of Drosophila melanogaster was investigated for a 2.7-kb region encompassing the Adh locus with ten four-cutter restriction enzymes. A total of 20 polymorphisms were detected, representing 15 restriction site polymorphisms, 4 length polymorphisms and the allozyme polymorphism. Variation at the DNA level was compared among St-Adh(F), St-Adh(S) and t-Adh(S) chromosomes. t-Adh(S) chromosomes show a higher level of variation than St-Adh(F) chromosomes. This suggests that In(2L)t arose before the fast/slow allozyme divergence in the evolutionary history of D. melanogaster.

scholarly journals Molecular and phenotypic variation of the white locus region in Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 120 (1) ◽  
pp. 199-212
Author(s):  
N Miyashita ◽  
C H Langley
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Restriction Site ◽  
Restriction Enzymes ◽  
Transcriptional Unit ◽  
X Chromosomes ◽  
Linkage Disequilibria ◽  
Restriction Sites ◽  
White Locus ◽  
Shock Locus

Abstract Restriction site and insertion/deletion polymorphism in a 45-kb region of the white locus on the X chromosome in Drosophila melanogaster was investigated for 64 X chromosome lines with six 6-cutter and ten 4-cutter restriction enzymes. A total of 109 polymorphisms were detected (54 restriction sites and 55 insertions/deletions). Estimated heterozygosity per nucleotide for this region (0.004-0.008) was similar to those of the Adh and 87A heat-shock locus regions located on the autosomes in D. melanogaster. This is contrary to a simple prediction based on the theory of mutation selection-balance of partially recessive deleterious mutants which predicts less variation on X chromosomes. Large linkage disequilibria between pairs of polymorphisms (including insertions and deletions) within the transcriptional unit (especially the 3' end of the 1st intron) were observed. As expected from population genetics theory, linkage disequilibria between these polymorphisms were greater for those pairs that are physically closer on the restriction map. Linkage equilibrium was typically observed when the pairs of sites were separated by 2 kb or more. Although significant between-line variation in eye pigment was observed (P less than 0.05), there is little evidence for strong associations between this phenotype and the polymorphisms at the DNA level.

scholarly journals Reduced variation in the yellow-achaete-scute region in natural populations of Drosophila melanogaster.

Genetics ◽  
1989 ◽  
Vol 122 (3) ◽  
pp. 607-615 ◽  
Author(s):  
M Aguade ◽  
N Miyashita ◽  
C H Langley
Keyword(s):  
Drosophila Melanogaster ◽  
Restriction Site ◽  
Natural Populations ◽  
Negative Relationship ◽  
Relative Number ◽  
Restriction Enzymes ◽  
Crossing Over ◽  
Length Polymorphisms ◽  
Polymorphic Restriction ◽  
Restriction Site Polymorphisms

Abstract Restriction map variation in 64 X chromosome lines extracted from three different populations of Drosophila melanogaster was investigated with seven six-nucleotide-recognizing restriction enzymes for a 106-kb region encompassing the yellow gene and the achaete-scute complex that is located in the region of reduced crossing over close to the telomere. Nine restriction site polymorphisms (out of 176 sites scored) and 19 length polymorphisms (15 insertions and 4 deletions) were detected. The estimated level of heterozygosity per nucleotide, H = 0.0003, is much lower than that reported for autosomal and sex-linked loci located in regions with normal levels of crossing over. The overall frequency of polymorphic restriction sites is reduced. Six out of nine restriction site polymorphisms are unique and the other three have frequencies less than 0.17. Some large insertions have reached relatively high frequencies, 0.08 to 0.17. Consistent with the theoretically predicted negative relationship between crossing over and the magnitude of linkage disequilibrium, an increase in the relative number of nonrandom associations was observed in the y-ac-sc region.

scholarly journals The genetic structure of natural populations of Drosophila melanogaster. XXII. Comparative study of DNA polymorphisms in northern and southern natural populations.

Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 753-761
Author(s):  
T S Takano ◽  
S Kusakabe ◽  
T Mukai
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Drift ◽  
Nucleotide Diversity ◽  
Restriction Site ◽  
Natural Populations ◽  
Dna Polymorphisms ◽  
Restriction Map ◽  
Random Genetic Drift ◽  
Two Populations ◽  
Restriction Site Polymorphisms

Abstract Restriction map variation in four gene regions (Adh, Amy, Pu and Gpdh) was surveyed for 86 second chromosomes from northern (Aomori) and southern (Ogasawara) Japanese populations of Drosophila melanogaster (43 chromosomes from each population). The regions examined cover a total of 62 kilobases. Estimates of nucleotide diversity (pi) were approximately constant across the gene regions and populations examined. The distribution of restriction site polymorphisms was compatible with the expectation from the neutral mutation-random genetic drift hypothesis, but insertion/deletion polymorphisms were not consistent with it. While the two populations shared a majority of restriction site polymorphisms, frequencies of individual restriction site variants were significantly different between the two populations at 7 out of 35 segregating sites. In addition, an insertion in the Amy region was found in 15 chromosomes from the Ogasawara sample but absent in the Aomori sample. A considerable difference was observed in the number of rare insertions and deletions between the two populations. The numbers of aberrations uniquely represented were 16 in the Ogasawara sample and only 3 in the Aomori sample. These findings suggest that the two populations were differentiated from each other to some degree by means of random genetic drift and/or other factors.

scholarly journals Genetic Screens for Factors Involved in the Notum Bristle Loss of Interspecific Hybrids Between Drosophila melanogaster and D. simulans

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 269-282
Author(s):  
Toshiyuki Takano-Shimizu
Keyword(s):  
Drosophila Melanogaster ◽  
Interspecific Cross ◽  
Species Variation ◽  
Genetic Screens ◽  
Pure Species ◽  
Epistatic Interactions ◽  
X Chromosomes ◽  
Powerful Means ◽  
Different Populations ◽  
Deficiency Screening

Abstract Interspecific cross is a powerful means to uncover hidden within- and between-species variation in populations. One example is a bristle loss phenotype of hybrids between Drosophila melanogaster and D. simulans, although both the pure species have exactly the same pattern of bristle formation on the notum. There exists a large amount of genetic variability in the simulans populations with respect to the number of missing bristles in hybrids, and the variation is largely attributable to simulans X chromosomes. Using nine molecular markers, I screened the simulans X chromosome for genetic factors that were responsible for the differences between a pair of simulans lines with high (H) and low (L) missing bristle numbers. Together with duplication-rescue experiments, a single major quantitative locus was mapped to a 13F–14F region. Importantly, this region accounted for most of the differences between H and L lines in three other independent pairs, suggesting segregation of H and L alleles at the single locus in different populations. Moreover, a deficiency screening uncovered several regions with factors that potentially cause the hybrid bristle loss due to epistatic interactions with the other factors.

scholarly journals The Regulatory Properties of Autonomous Subtelomeric P Elements Are Sensitive to a Suppressor of variegation in Drosophila melanogaster

Genetics ◽  
1996 ◽  
Vol 143 (4) ◽  
pp. 1663-1674 ◽  
Author(s):  
Stéphane Ronsseray ◽  
Monique Lehmann ◽  
Danielle Nouaud ◽  
Dominique Anxolabéhère
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Recombination ◽  
Natural Populations ◽  
P Element ◽  
Single Element ◽  
Heterochromatin Protein 1 ◽  
X Chromosomes ◽  
P Elements ◽  
Associated Sequences ◽  
Regulatory Properties

Abstract Genetic recombination was used in Drosophila melanogaster to isolate P elements, inserted at the telomeres of X chromosomes (cytological site 1A) from natural populations, in a genetic background devoid of other P elements. We show that complete maternally inherited P repression in the germline (P cytotype) can be elicited by only two autonomous P elements at 1A and that a single element at this site has partial regulatory properties. The analysis of the surrounding chromosomal regions of the P elements at 1A shows that in all cases these elements are flanked by Telomeric Associated Sequences, tandemly repetitive noncoding sequences that have properties of heterochromatin. In addition, we show that the regulatory properties of P elements at 1A can be inhibited by some of the mutant alleles of the Su(var)205 gene and by a deficiency of this gene. However, the regulatory properties of reference P strains (Harwich and Texas 007) are not impaired by Su(var)205 mutations. Su(var)205 encodes Heterochromatin Protein 1 (HP1). These results suggest that the HP1 dosage effect on the P element properties is sitedependent and could involve the structure of the chromatin.

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