A comprehensive study of genic variation in natural populations of Drosophila melanogaster. V. Structural–functional constraints on protein molecules and enzymes and the levels and patterns of variation among genes

Genome ◽  
1992 ◽  
Vol 35 (1) ◽  
pp. 109-119 ◽  
Author(s):  
Rama S. Singh
Keyword(s):  
Molecular Structure ◽  
Drosophila Melanogaster ◽  
Balancing Selection ◽  
Natural Populations ◽  
Null Alleles ◽  
Subunit Structure ◽  
Functional Constraints ◽  
Enzyme Variation ◽  
Subunit Size ◽  
Substrate Group

Ever since isozyme–allozyme polymorphisms were detected there has been an incessant effort to relate the amount of observed protein variation to various aspects of molecular structure and function. Structural–functional constraints can limit the amount of overall genie variation, and the observed variation can be due to neutral mutation and random genetic drift, mutation–selection balance, or balancing selection. The present analysis of structural–functional constraints on gene–enzyme variation in natural populations of Drosophila melanogaster shows that while both subunit size and substrate group show significant effects on number of alleles and mean heterozygosity, only substrate group affects population structure significantly. Subunit structure (monomer vs. multimer), IUB enzyme class (e.g., tranferase, lyase), and tolerance of null alleles showed no significant effect on level or pattern of variation. While partly interdependent these results suggest that efforts should be made to distinguish between constraints arising from molecular structure and physiological function.Key words: structural–functional constraints, subunit size, gene-enzyme variation, selection, neutrality.

scholarly journals Behavioral variation in Drosophila melanogaster: no evidence for common alleles of large- effect at the foraging gene in a population from North Carolina, USA

2014 ◽  
Author(s):  
Thomas Turner ◽  
Christopher C Giauque ◽  
Daniel R Schrider ◽  
Andrew D Kern
Keyword(s):  
North Carolina ◽  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Foraging Behavior ◽  
Additional Data ◽  
Balancing Selection ◽  
Natural Populations ◽  
Specific Population ◽  
Foraging Gene ◽  
Population Genetic Variation

It has been postulated that natural populations of Drosophila melanogaster are comprised of two behavioral morphs termed "rover" and "sitter", and that this variation is caused mainly by large-effect alleles at a single locus. Contrary to common assertions, however, published support for the existence of common large effect alleles in nature is quite limited. To further investigate, we quantified the foraging behavior of 36 sequenced strains from a natural population, performed an association study, and described patterns of molecular evolution at the foraging locus. Though there was significant variation in foraging behavior among genotypes, this variation was continuously distributed and not significantly associated with genetic variation at the foraging gene. Patterns of molecular population genetic variation at this gene also provide no support for the hypothesis that for is a target of recent balancing selection. Though our data only apply to this specific population, we propose that additional data is required to support a hypothesis of common alleles of large effect on foraging behavior in nature.

scholarly journals Enzyme null alleles in natural populations of Drosophila melanogaster: Frequencies in a North Carolina population

1980 ◽  
Vol 77 (2) ◽  
pp. 1091-1095 ◽  
Author(s):  
R. A. Voelker ◽  
C. H. Langley ◽  
A. J. L. Brown ◽  
S. Ohnishi ◽  
B. Dickson ◽  
...  
Keyword(s):  
North Carolina ◽  
Drosophila Melanogaster ◽  
Natural Populations ◽  
Null Alleles ◽  
Carolina Population

scholarly journals NULL ALLELE FREQUENCIES AT ALLOZYME LOCI IN NATURAL POPULATIONS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1981 ◽  
Vol 99 (1) ◽  
pp. 151-156
Author(s):  
Charles H Langley ◽  
Robert A Voelker ◽  
Andrew J Leigh Brown ◽  
Seido Ohnishi ◽  
Barbara Dickson ◽  
...  
Keyword(s):  
North Carolina ◽  
Drosophila Melanogaster ◽  
Null Allele ◽  
Natural Populations ◽  
Allele Frequencies ◽  
Null Alleles ◽  
Carolina Population ◽  
The Mean ◽  
Allozyme Loci ◽  
Two Populations

ABSTRACT We have sampled a London population of Drosophila melanogaster for null alleles at twenty-five allozyme loci. The same loci and biochemical techniques were used as in our previous survey of a North Carolina population (Voelker et al. 1980). This second survey is completely concordant with the first. No nulls were detected among the five X-linked loci. The mean frequency of nulls at the twenty autosomal loci was 0.0023. Although there is significant interlocus heterogeneity, the two populations appear to have the same frequencies at each locus. This suggests that null alleles at these allozyme loci are in mutation-selection balance, and we estimate the average heterozygous effect of an allozyme null to be 0.0015. Consideration of allozyme null-allele frequencies, the effects of allozyme null alleles on viability and fertility and the generally greater amount of genetic variability at allozyme loci determined by electrophoresis lead us to doubt the validity of generalizing from allozyme data to the whole genome.

scholarly journals The Relationship Between Dipeptidase Activity Variation and Larval Viability in Drosophila melanogaster

Genetics ◽  
1987 ◽  
Vol 117 (3) ◽  
pp. 503-512
Author(s):  
Kazuo Hiraizumi ◽  
Cathy C Laurie
Keyword(s):  
Drosophila Melanogaster ◽  
Null Allele ◽  
Natural Populations ◽  
Null Alleles ◽  
Adult Survival ◽  
Free Form ◽  
Alternative Mechanism ◽  
Fitness Components ◽  
Restrictive Diet

ABSTRACT The enzyme dipeptidase-A (DIP-A) in Drosophila melanogaster is coded by a second chromosome locus that is polymorphic for three allozymes in natural populations. DIP-A appears to be the only enzyme in D. melanogaster capable of hydrolyzing the dipeptide glycyl-l-isoleucine, since flies homozygous for null alleles at this locus have no detectable glycyl- l-isoleucine-ase activity. DIP-A activity occurs in many tissues and throughout development, but is particularly high in the larval midgut, suggesting an important role in protein digestion. These observations suggested an experimental design for investigating the adaptive significance of genetic variation in DIP-A activity. Fitness components of DIP-A variants could be estimated and compared under two environmental conditions (defined diets under axenic conditions). In the restrictive environment, the essential amino acid l-isoleucine is provided only in the form of glycyl-l-isoleucine, whereas in the permissive environment, l-isoleucine is provided in free form. We predicted that DIP-A activity would be essential in the restrictive, but not in the permissive environment. The results reported here clearly contradict this prediction. Two stocks homozygous for DIP-A null alleles from different geographic locations are each viable on the restrictive diet. Furthermore, relative viability experiments in which null allele larvae compete with larvae having DIP-A activity provide no evidence for even a partial reduction in egg to adult survival on the restrictive diet. Apparently, the null allele larvae have some alternative mechanism for obtaining l-isoleucine from the dipeptide, even though no glycyl-l-isoleucine-ase activity can be detected in vitro. These results, along with the viability of null alleles for many other enzymes, support the idea that eukaryotes have an intricate network of alternative biochemical pathways through which the same necessary function may be achieved. Such "buffering capacity" makes it very difficult to analyze the effects of enzyme variants on fitness components.

scholarly journals Two modes of balancing selection in Drosophila melanogaster: overcompensation and overdominance.

Genetics ◽  
1991 ◽  
Vol 128 (2) ◽  
pp. 381-391
Author(s):  
T X Peng ◽  
A Moya ◽  
F J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Balancing Selection ◽  
Natural Populations ◽  
Frequency Dependent ◽  
Frequency Dependent Selection ◽  
Designed Experiments ◽  
Two Temperatures ◽  
Limiting Resources ◽  
Uniform Population

Abstract Overdominance is often invoked to account for the extensive polymorphisms found in natural populations of organisms; overcompensation, however, may be equally or more important. Overcompensation occurs when limiting resources are better exploited by a genetically mixed than by a uniform population, and is often causally related to frequency-dependent selection. We have designed experiments to test whether overcompensation occurs in Drosophila melanogaster, using the Sod locus as a marker. Tests are made at each of two densities and two temperatures for cultures with desired genetic compositions. Both temperature and density have statistically significant effects on the per-female productivity of the cultures. More important, there are strong effects due to overcompensation. Cultures that are more polymorphic are also more productive than less polymorphic ones even when the level of individual heterozygosity is the same in all. There is also overdominance for the Sod locus: the heterozygotes are more productive than either homozygote at every temperature and density, and the differences are statistically significant in several cases. These results corroborate previous studies showing that overdominance may contribute to the maintenance of the Sod polymorphisms. Moreover, our results indicate that the significance of overcompensation as a mechanism to account for polymorphism in natural populations deserves further investigation.

Transcription analysis of alcohol dehydrogenase null alleles from natural populations of Drosophila melanogaster

Genome ◽  
1988 ◽  
Vol 30 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Allan L. Freeth ◽  
John B. Gibson ◽  
Ann V. Wilks
Keyword(s):  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Northern Blot ◽  
Natural Populations ◽  
Molecular Properties ◽  
Southern Analysis ◽  
Null Alleles ◽  
Normal Allele ◽  
Transcription Analysis

Southern analysis of 19 Adh null activity alleles isolated from Tasmanian populations of Drosophila melanogaster have shown that there are no detectable insertions or deletions in an 11.8-kb region that contains the gene. Northern blot analyses of the null alleles have shown that they all produce a transcript about 100 bases longer than that produced by the normal allele and they accumulate a precursor of 1800 bases. The amount of the major transcript produced by the null alleles is about 10% of that produced by normal alleles. The molecular properties of the null alleles suggest that they share a common origin.Key words: alcoahol dehydrogenase, null alleles, mRNA, Drosophila melanogaster.

scholarly journals Female Genotypes Affect Sperm Displacement in Drosophila

Genetics ◽  
1998 ◽  
Vol 149 (3) ◽  
pp. 1487-1493 ◽  
Author(s):  
Andrew G Clark ◽  
David J Begun
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Natural Populations ◽  
Isogenic Line ◽  
Female Fitness ◽  
Sperm Displacement ◽  
Extensive Variation ◽  
Polymorphic Genes ◽  
Displacement Parameter ◽  
Competitive Success

Abstract Differential success of sperm is likely to be an important component of fitness. Extensive variation among male genotypes in competitive success of sperm in multiply mated females has been documented for Drosophila melanogaster. However, virtually all previous studies considered the female to be a passive vessel. Nevertheless, under certain conditions female fitness could be determined by her role in mediating use of sperm from multiple males. Here we ask whether females differ among genotypes in their tendency to exhibit last-male precedence. Competition of sperm from two tester male genotypes (bwD and B3-09, a third-chromosome isogenic line from Beltsville, MD) was quantified by doubly mating female lines that had been rendered homozygous for X, second, or third chromosomes isolated from natural populations. The composite sperm displacement parameter, P2′, was highly heterogeneous among lines, whether or not viability effects were compensated, implying the presence of polymorphic genes affecting access of sperm to eggs. Genetic variation of this type is completely neutral in the absence of pleiotropy or interaction between variation in the two sexes.

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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