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 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 Naturally occurring variation in the restriction map of the amy region of Drosophila melanogaster.

Genetics ◽  
1988 ◽  
Vol 119 (3) ◽  
pp. 619-629
Author(s):  
C H Langley ◽  
A E Shrimpton ◽  
T Yamazaki ◽  
N Miyashita ◽  
Y Matsuo ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Restriction Site ◽  
Natural Populations ◽  
Alpha Amylase ◽  
Low Frequencies ◽  
Linkage Disequilibria ◽  
Restriction Sites ◽  
Site Variation ◽  
Transcriptional Units ◽  
Polymorphic Restriction

Abstract The restriction maps of 85 alleles of the Amy region of Drosophila melanogaster from natural populations were surveyed. A subset of these were also scored for allozyme phenotype and adult enzyme activity of alpha-amylase. Large insertions were found in 12% of the alleles in a 15-kb region surrounding the two transcriptional units of the duplicated Amy locus. The low frequencies at which each of these large insertions were found are consistent with earlier reports of variation in other loci. Four small deletions were found in the region 5' to the Amy genes. Each was also rare in the population. Restriction site variation provided an estimate of per nucleotide heterozygosity of 0.006. Several statistically significant linkage disequilibria were observed between four polymorphic restriction sites and the allozymes. Adult alpha-amylase activity was correlated with the allozymes and with the polymorphism at one restriction site close to the transcriptional units.

scholarly journals Evidence of extensive genetic exchange in the rp49 region among polymorphic chromosome inversions in Drosophila subobscura.

Genetics ◽  
1990 ◽  
Vol 126 (2) ◽  
pp. 417-426
Author(s):  
J Rozas ◽  
M Aguadé
Keyword(s):  
Restriction Site ◽  
Haplotype Diversity ◽  
Natural Populations ◽  
Drosophila Subobscura ◽  
Genetic Exchange ◽  
Nucleotide Variation ◽  
Chromosome Inversions ◽  
Length Polymorphisms ◽  
Rp49 Gene ◽  
Restriction Site Polymorphisms

Abstract Restriction map variation in 107 lines extracted from two natural populations of Drosophila subobscura was investigated with seven four-nucleotide-recognizing enzymes in a 1.6-kb region including the rp49 gene, that is located very close to the proximal breakpoint of inversion O3. Fourteen restriction site and 8 length polymorphisms, resulting in 73 haplotypes, have been identified. Estimated heterozygosity per nucleotide, pi = 0.0045, is comparable to the average nucleotide variation observed in Drosophila melanogaster. Because of the location of the rp49 region in D. subobscura, variation in three different gene arrangements-Ost, O3 + 4 and O3 + 4 + 8-has been compared. Out of 14 restriction site polymorphisms, 3 are shared by Ost, O3 + 4 and O3 + 4 + 8, and 3 additional ones are shared by Ost and O3 + 4, evidencing extensive genetic exchange among these polymorphic inversions. In agreement with previous data, the higher level of variation of O3 + 4 (as measured by haplotype diversity and nucleotide variation) suggests that O3 + 4 may be ancestral in relationship to extant gene arrangements.

scholarly journals Intraspecific and interspecific variation at the y-ac-sc region of Drosophila simulans and Drosophila melanogaster.

Genetics ◽  
1992 ◽  
Vol 130 (4) ◽  
pp. 805-816 ◽  
Author(s):  
J M Martín-Campos ◽  
J M Comerón ◽  
N Miyashita ◽  
M Aguadé
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Length Polymorphism ◽  
Restriction Site ◽  
Natural Populations ◽  
Restriction Enzymes ◽  
Drosophila Simulans ◽  
Population Subdivision ◽  
Telomeric Region ◽  
Length Variation

Abstract A 2.2-kb region including the ac gene of Drosophila simulans has been sequenced. Interspecific divergence between Drosophila melanogaster and D. simulans was estimated as 0.0695 and 0.0558 for silent and for all sites, respectively. Estimated silent site divergence for the ac region is comparable to that estimated for other regions of the genome between these species, indicating that silent sites of the ac region are not under significantly stronger functional constraint. Intraspecific variation in both species was also investigated. Restriction-site and length polymorphism in the ac region of D. simulans has been investigated for 103 X chromosome lines sampled from three natural populations in Spain using eight four-cutter restriction enzymes. Neither restriction-site nor length variation was detected in the three populations surveyed. In D. melanogaster restriction-site and length polymorphism in all major transcription units of the y-ac-sc region (23.1-kb region) has been studied using four four-cutter restriction enzymes for 245 X chromosome lines sampled from 10 natural populations (seven from Europe, two from North America and one from Japan). Fourteen restriction-site and 28 length polymorphisms were detected. There was some indication of population subdivision for North American vs. European samples of D. melanogaster. The frequency spectrum of restriction-site polymorphisms in European populations was skewed toward rarer frequencies than predicted by the neutral theory. Comparison of silent site variation at this telomeric region with that in the Adh 5'-flanking region showed a reduced level of heterozygosity in the y-ac-sc region. Since interspecific silent divergence is not reduced in the y-ac-sc region as compared to other regions, the reduction in standing levels of variation at this telomeric locus in both D. simulans and D. melanogaster is most easily explained by a hitchhiking effect of linked selected substitutions.

scholarly journals A comprehensive study of genic variation in natural populations of Drosophila melanogaster. IV. Mitochondrial DNA variation and the role of history vs. selection in the genetic structure of geographic populations.

Genetics ◽  
1991 ◽  
Vol 129 (1) ◽  
pp. 103-117
Author(s):  
L R Hale ◽  
R S Singh
Keyword(s):  
Mitochondrial Dna ◽  
Drosophila Melanogaster ◽  
Restriction Site ◽  
Far East ◽  
Natural Populations ◽  
Size Variation ◽  
Restriction Enzymes ◽  
Western Hemisphere ◽  
Small Scale ◽  
Coding Region

Abstract Preliminary studies with restriction fragment length polymorphisms of mitochondrial DNA (mtDNA) in natural populations of Drosophila melanogaster revealed considerable variation in terms of nucleotide sequence and overall size. In this report we present data from more isofemale lines and more restriction enzymes, and explore the utility of the data in inferring a colonization history of this species. Size variation in the noncoding A + T-rich region is particularly plentiful, with size variants occurring in all restriction site haplotypes in all populations. We report here classes of small-scale mobility polymorphisms (apparent range of 20 bp) in specific restriction fragments in the coding region. The variation in one such fragment appears to be generated even more rapidly than in the noncoding region. On the basis of the distribution of restriction site haplotypes, the species range can be divided into three major regions along longitudinal lines: Euro-African populations are the most diverse and are taken to be oldest; Far East populations have a complex distribution of haplotypes; Western Hemisphere populations are the least diverse and are interpreted to be the youngest. The history inferred from mtDNA alone is remarkably similar to one based on several nuclear markers. The mtDNA haplotype distribution is also very different from that of allozymes in these same populations. We interpret this as further evidence that natural selection is still the most parsimonious explanation for the parallel latitudinal allozyme clines in this species.

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 Reciprocal recombination and the evolution of the ribosomal gene family of Drosophila melanogaster.

Genetics ◽  
1989 ◽  
Vol 122 (3) ◽  
pp. 617-624 ◽  
Author(s):  
S M Williams ◽  
J A Kennison ◽  
L G Robbins ◽  
C Strobeck
Keyword(s):  
Drosophila Melanogaster ◽  
Gene Family ◽  
Ribosomal Rna ◽  
Natural Populations ◽  
Ribosomal Gene ◽  
Gene Region ◽  
Ribosomal Rna Gene ◽  
Reciprocal Recombination ◽  
Y Chromosomes ◽  
Length Polymorphisms

Abstract The role of reciprocal recombination in the coevolution of the ribosomal RNA gene family on the X and Y chromosomes of Drosophila melanogaster was assessed by determining the frequency and nature of such exchange. In order to detect exchange events within the ribosomal RNA gene family, both flanking markers and restriction fragment length polymorphisms within the tandemly repeated gene family were used. The vast majority of crossovers between flanking markers were within the ribosomal RNA gene region, indicating that this region is a hotspot for heterochromatic recombination. The frequency of crossovers within the ribosomal RNA gene region was approximately 10(-4) in both X/X and X/Y individuals. In conjunction with published X chromosome-specific and Y chromosome-specific sequences and restriction patterns, the data indicate that reciprocal recombination alone cannot be responsible for the observed variation in natural populations.

scholarly journals Lack of underdominance in a naturally occurring pericentric inversion in Drosophila melanogaster and its implications for chromosome evolution.

Genetics ◽  
1991 ◽  
Vol 129 (3) ◽  
pp. 791-802
Author(s):  
J A Coyne ◽  
S Aulard ◽  
A Berry
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Genetic Drift ◽  
Related Species ◽  
Pericentric Inversion ◽  
Chromosome Evolution ◽  
Natural Populations ◽  
Crossing Over ◽  
Closely Related Species ◽  
Naturally Occurring

Abstract In(2LR)PL is a large pericentric inversion polymorphic in populations of Drosophila melanogaster on two Indian Ocean islands. This polymorphism is puzzling: because crossing over in female heterokaryotypes produces inviable zygotes, such inversions are thought to be underdominant and should be quickly eliminated from populations. The observed fixation for such inversions among related species has led to the idea that genetic drift can cause chromosome evolution in opposition to natural selection. We found, however, that In(2LR)PL is not underdominant for fertility, as heterokaryotypic females produce perfectly viable eggs. Genetic analysis shows that the lack of underdominance results from the nearly complete absence of crossing over in the inverted region. This phenomenon is probably caused by mechanical and not genetic factors, because crossing over is not suppressed in In(2LR)PL homokaryotypes. Our observations do not support the idea that the fixation of pericentric inversions among closely related species implies the action of genetic drift overcoming strong natural selection in very small populations. If chromosome arrangements vary in their underdominance, it is those with the least disadvantage as heterozygotes, like In(2LR)PL, that will be polymorphic or fixed in natural populations.

Haemophilia A in a Female: Study of a Family Using Intragenic and Extragenic Restriction Site Polymorphisms

1988 ◽  
Vol 60 (01) ◽  
pp. 102-106 ◽  
Author(s):  
G Piétu ◽  
N Thomas-Maison ◽  
P Sié ◽  
M J Larrieu ◽  
D Meyer
Keyword(s):  
Cdna Probe ◽  
Normal Karyotype ◽  
Restriction Enzymes ◽  
Carrier Status ◽  
Haemophilia A ◽  
Bleeding Tendency ◽  
Excessive Bleeding ◽  
Length Polymorphisms ◽  
The Family ◽  
Restriction Site Polymorphisms

SummaryRestriction fragment length polymorphisms(RFLPs) were studied in a large Algerian family which includes 6 haemophiliacs and a previously described case of female haemophilia A. The female propositus is 66 years old with a normal karyotype. Her parents are first cousins. Her 3 sons are haemophiliacs and her 3 daughters with affected children are obligate carriers. The proband has an excessive bleeding tendency and markedly reduced levels of F. VIII (VIII C 0.03 U/ml, VIII Ag 0.01 U/ml) with elevated vWF Ag (2.30 U/ml), similar to the levels observed in affected males from the family. Four RFLPs can be identified by Southern blotting after digesting genomic DNA with the restriction enzymes Bcl I, Bgl I, Kpn I/Xba I and Taq I and hybridization with a 647 bp Stu I/Sca I F. VIII genomic probe, a 1.8 Kb EcoRI F. VIII cDNA probe, a 1.0 Kb EcoRI/Sst I fragment of intron 22 and the extragenic probe ST 14, respectively. With these four RFLPS, the propositus was found to be homozygous for the alleles segregating in this family with the abnormal X-chromosome. The carrier status was proven in a granddaughter and excluded in another. In conclusion, this RFLP linkage analysis is another argument to suggest that the propositus, a rare case of female haemophilia, is homozygous for the abnormal gene.

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.

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