HIDDEN ELECTROPHORETIC VARIATION AT THE XANTHINE DEHYDROGENASE LOCUS IN A NATURAL POPULATION OF DROSOPHILA MELANOGASTER

Genetics ◽  
1983 ◽  
Vol 104 (2) ◽  
pp. 301-315
Author(s):  
Barbara Ann Buchanan ◽  
Diana L E Johnson

ABSTRACT Sixty-two isochromosomal lines of D. melanogaster were screened for cryptic electrophoretic variation at the xanthine dehydrogenase (XDH) locus. Sequential polyacrylamide vertical slab gel electrophoresis was performed using four electrophoretic criteria. A total of 15 classes of electromorphs were revealed. D. melanogaster appears to exhibit as much polymorphism at this locus as other extensively studied Drosophila species.—No evidence for loci on the X or second chromosomes which modified XDH mobility was found. Six of the electromorphs were mapped to the Xdh (ry) structural locus. Eight of the remaining nine classes exhibited mobility variation consistent with structural variation at the Xdh locus. The final class exhibited aberrant patterns and is under further study.

Genetics ◽  
1974 ◽  
Vol 76 (2) ◽  
pp. 289-299
Author(s):  
Margaret McCarron ◽  
William Gelbart ◽  
Arthur Chovnick

ABSTRACT A convenient method is described for the intracistronic mapping of genetic sites responsible for electrophoretic variation of a specific protein in Drosophila melanogaster. A number of wild-type isoalleles of the rosy locus have been isolated which are associated with the production of electrophoretically distinguishable xanthine dehydrogenases. Large-scale recombination experiments were carried out involving null enzyme mutants induced on electrophoretically distinct wild-type isoalleles, the genetic basis for which is followed as a nonselective marker in the cross. Additionally, a large-scale recombination experiment was carried out involving null enzyme rosy mutants induced on the same wild-type isoallele. Examination of the electrophoretic character of crossover and convertant products recovered from the latter experiment revealed that all exhibited the same parental electrophoretic character. In addition to documenting the stability of the xanthine dehydrogenase electrophoretic character, this observation argues against a special mutagenesis hypothesis to explain conversions resulting from allele recombination studies.


Genetics ◽  
1981 ◽  
Vol 98 (4) ◽  
pp. 817-831
Author(s):  
George Johnson ◽  
Victoria Finnerty ◽  
Daniel Hartl

ABSTRACT Second chromosomes of D. melanogaster were isolated from a single natural population, and 40 were analyzed by gel-sieving electrophoresis for the presence of polymorphic loci on chromosome 2 that act to modify xanthine dehydrogenase and/or aldehyde oxidase, whose structural genes map to chromosome 3. Clear evidence of polymorphism for one or more xanthine dehydrogenase modifier loci was obtained.


Genetics ◽  
1980 ◽  
Vol 95 (2) ◽  
pp. 467-475
Author(s):  
Martin Kreitman

ABSTRACT Ninety-six isochromosomal lines of Drosophila melanogaster from a natural population were screened electrophoretically for unusual mobility variants at the alcohol dehydrogenase locus, using a total of eight conditions of acrylamide electrophoresis. No additional mobility variation was found among the 50 "slow" and 46 "fast" mobility lines beyond that detected by standard methods of electrophoresis. However, two thermostability variants recovered by R. MILKMAN from a natural population, whose electrophoretic mobilities were previously thought to be indistinguishable from those of "standard" alleles, are distinguishable from the standard elcctromorphs by these procedures. These results suggest that the Adhlocus, although polymorphic, does not harbor substantial amounts of "hidden" allelic variability. This study also reports the appearance of substantial mobility variation among isogenic lines that can be induced under specific conditions of sample preparation involving the pretreatment of samples with NAD and acetone. However, genetic analysis demonstrates that this variability cannot be attributed to allelic differences at the structural locus, but instead appears to be dependent upon the concentration of the enzyme in a sample. These results are discussed in relation to the distribution of allelic variation at other enzyme loci.


Genetics ◽  
1974 ◽  
Vol 78 (3) ◽  
pp. 869-886
Author(s):  
William M Gelbart ◽  
Margaret McCarron ◽  
Janardan Pandey ◽  
Arthur Chovnick

Abstract Experiments are described that provide an opportunity to estimate the genetic limits of the structural (amino acid coding) portion of the rosy locus (3: 52.0) in Drosophila melanogaster, which controls the enzyme, xanthine dehydrogenase (XDH) . This is accomplished by mapping experiments which localize sites responsible for electrophoretic variation in the enzyme on the known genetic map of null-XDH rosy mutants. Electrophoretic sites are distributed along a large portion of the null mutant map. A cis-trans test involving electrophoretic variants in the left- and right-hand portions of the map leads to the conclusion that the entire region between these variants is also structural. Hence most, if not all, of the null mutant map of the rosy locus contains structural information for the amino acid sequence of the XDH polypeptide. Consideration is given to the significance of the present results for the general problem of gene organization in higher eukaryotes.


Genetics ◽  
1974 ◽  
Vol 77 (3) ◽  
pp. 569-589
Author(s):  
Martin L Tracey ◽  
Francisco J Ayala

ABSTRACT Recent studies of genetically controlled enzyme variation lead to an estimation that at least 30 to 60% of the structural genes are polymorphic in natural populations of many vertebrate and invertebrate species. Some authors have argued that a substantial proportion of these polymorphisms cannot be maintained by natural selection because this would result in an unbearable genetic load. If many polymorphisms are maintained by heterotic natural selection, individuals with much greater than average proportion of homozygous loci should have very low fitness. We have measured in Drosophila melanogaster the fitness of flies homozygous for a complete chromosome relative to normal wild flies. A total of 37 chromosomes from a natural population have been tested using 92 experimental populations. The mean fitness of homozygous flies is 0.12 for second chromosomes, and 0.13 for third chromosomes. These estimates are compatible with the hypothesis that many (more than one thousand) loci are maintained by heterotic selection in natural populations of D. melanogaster.


Genetics ◽  
1991 ◽  
Vol 129 (4) ◽  
pp. 1099-1109 ◽  
Author(s):  
A G Reaume ◽  
D A Knecht ◽  
A Chovnick

Abstract The rosy gene in Drosophila melanogaster codes for the enzyme xanthine dehydrogenase (XDH). Mutants that have no enzyme activity are characterized by a brownish eye color phenotype reflecting a deficiency in the red eye pigment. Xanthine dehydrogenase is not synthesized in the eye, but rather is transported there. The present report describes the ultrastructural localization of XDH in the Drosophila eye. Three lines of evidence are presented demonstrating that XDH is sequestered within specific vacuoles, the type II pigment granules. Histochemical and antibody staining of frozen sections, as well as thin layer chromatography studies of several adult genotypes serve to examine some of the factors and genic interactions that may be involved in transport of XDH, and in eye pigment formation. While a specific function for XDH in the synthesis of the red, pteridine eye pigments remains unknown, these studies present evidence that: (1) the incorporation of XDH into the pigment granules requires specific interaction between a normal XDH molecule and one or more transport proteins; (2) the structural integrity of the pigment granule itself is dependent upon the presence of a normal balance of eye pigments, a notion advanced earlier.


Heredity ◽  
2021 ◽  
Author(s):  
Dau Dayal Aggarwal ◽  
Sviatoslav Rybnikov ◽  
Shaul Sapielkin ◽  
Eugenia Rashkovetsky ◽  
Zeev Frenkel ◽  
...  

2009 ◽  
Vol 87 (7) ◽  
pp. 635-641 ◽  
Author(s):  
S. Havard ◽  
P. Eslin ◽  
G. Prévost ◽  
G. Doury

Unable to form cellular capsules around large foreign bodies, the species Drosophila subobscura Collin in Gordon, 1936 was previously shown devoid of lamellocytes, the capsule-forming hemocytes in Drosophila melanogaster Meigen, 1830. This unusual case of deficiency in encapsulation ability was remarkable enough to motivate further investigations in phylogenetically related species of the obscura group. Like D. subobscura, the species Drosophila azteca Sturtevant and Dobzhansky, 1936, Drosophila bifasciata Pomini, 1940, Drosophila guanche Monclus, 1976, Drosophila miranda Dobzhansky, 1935, Drosophila persimilis Dobzhansky and Epling, 1944, and Drosophila pseudoobcura Frovola and Astaurov, 1929 were found to be unable to encapsulate large foreign bodies and also to lack lamellocytes. Surprisingly, Drosophila affinis Sturtevant, 1916, Drosophila tolteca Patterson and Mainland, 1944, and Drosophila obscura Fallen, 1823 were capable of mounting cellular capsules, although their encapsulation abilities remained weak. These three species were free of lamellocytes but possessed small pools of never before described “atypical hemocytes” present in the hemolymph when capsules were formed.


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