scholarly journals Distribution of Nonrandom Associations Between Pairs of Protein Loci Along the Third Chromosome of Drosophila melanogaster

Genetics ◽  
2002 ◽  
Vol 161 (4) ◽  
pp. 1539-1550 ◽  
Author(s):  
Carlos Zapata ◽  
Concepción Núñez ◽  
Teresa Velasco
Keyword(s):  
Drosophila Melanogaster ◽  
Statistical Power ◽  
Neutral Theory ◽  
Natural Populations ◽  
Estimation Method ◽  
Antioxidant Defense System ◽  
Hormonal Control ◽  
Long Distance ◽  
The Third ◽  
Outcrossing Species

Abstract The within-chromosome distribution of gametic disequilibrium (GD) between protein loci, and the underlying evolutionary factors of this distribution, are still largely unknown. Here, we report a detailed study of GD between a large number of protein loci (15) spanning 87% of the total length of the third chromosome of Drosophila melanogaster in a large sample of haplotypes (600) drawn from a single natural population. We used a sign-based GD estimation method recently developed for multiallelic systems, which considerably increases both the statistical power and the accuracy of estimation of the intensity of GD. We found that strong GD between pairs of protein loci was widespread throughout the chromosome. In total, 22% of both the pairs of alleles and pairs of loci were in significant GD, with mean intensities (as measured by D′ coefficients) of 0.43 and 0.31, respectively. In addition, strong GD often occurs between loci that are far apart. By way of illustration, 32% of the allele pairs in significant GD occurred within pairs of loci separated by effective frequencies of recombination (EFRs) of 15–20 cM, the mean D′ value being 0.49. These observations are in sharp contrast with previous studies showing that GD between protein loci is rarely found in natural populations of outcrossing species, even between very closely linked loci. Interestingly, we found that most instances of significant interallelic GD (68%) involved functionally related protein loci. Specifically, GD was markedly more frequent between protein loci related by the functions of hormonal control, molybdenum control, antioxidant defense system, and reproduction than between loci without known functional relationship, which is indicative of epistatic selection. Furthermore, long-distance GD between functionally related loci (mean EFR 9 cM) suggests that epistatic interactions must be very strong along the chromosome. This evidence is hardly compatible with the neutral theory and has far-reaching implications for understanding the multilocus architecture of the functional genome. Our findings also suggest that GD may be a useful tool for discovering networks of functionally interacting proteins.

scholarly journals GENETIC AND BIOCHEMICAL BASIS OF ENZYME ACTIVITY VARIATION IN NATURAL POPULATIONS. I. ALCOHOL DEHYDROGENASE IN DROSOPHILA MELANOGASTER

Genetics ◽  
1978 ◽  
Vol 89 (2) ◽  
pp. 371-388
Author(s):  
John F McDonald ◽  
Francisco J Ayala
Keyword(s):  
Gene Regulation ◽  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Natural Populations ◽  
Difficult Problem ◽  
Regulatory Genes ◽  
Biochemical Basis ◽  
Evolutionary Consequence ◽  
The Third ◽  
Adh Activity

ABSTRACT Recent studies by various authors suggest that variation in gene regulation may be common in nature, and might be of great evolutionary consequence; but the ascertainment of variation in gene regulation has proven to be a difficult problem. In this study, we explore this problem by measuring alcohol dehydrogenase (ADH) activity in Drosophila melanogaster strains homozygous for various combinations of given second and third chromosomes sampled from a natural population. The structural locus (Adh) coding for ADH is on the second chromosome. The results show that: (1) there are genes, other than Adh, that affect the levels of ADH activity; (2) at least some of these "regulatory" genes are located on the third chromosome, and thus are not adjacent to the Adh locus; (3) variation exists in natural populations for such regulatory genes; (4) the effect of these regulatory genes varies as they interact with different second chromosomes; (5) third chromosomes with high-activity genes are either partially or completely dominant over chromosomes with low-activity genes; (6) the effects of the regulatory genes are pervasive throughout development; and (7) the third chromosome genes regulate the levels of ADH activity by affecting the number of ADH molecules in the flies. The results are consistent with the view that the evolution of regulatory genes may play an important role in adaptation.

scholarly journals Studies of esterase 6 in Drosophila melanogaster: XIV. Variation of esterase 6 levels controlled by unlinked genes in natural populations

1984 ◽  
Vol 43 (2) ◽  
pp. 181-190 ◽  
Author(s):  
Craig S. Tepper ◽  
Anne L. Terry ◽  
James E. Holmes ◽  
Rollin C. Richmond
Keyword(s):  
Drosophila Melanogaster ◽  
Structural Gene ◽  
X Chromosome ◽  
Genetic Background ◽  
Natural Populations ◽  
Regulatory Elements ◽  
Regulatory Locus ◽  
The Third ◽  
Esterase 6 ◽  
Activity Modifiers

SUMMARYThe esterase 6 (Est-6) locus in Drosophila melanogaster is located on the third chromosome and is the structural gene for a carboxylesterase (E.C.3.1.1.1) and is polymorphic for two major electromorphs (slow and fast). Isogenic lines containing X chromosomes extracted from natural populations and substituted into a common genetic background were used to detect unlinked factors that affect the activity of the Est-6 locus. Twofold activity differences of esterase 6 (EST 6) were found among males from these derived lines, which differ only in their X chromosome. These unlinked activity modifiers identify possible regulatory elements. Immunoelectrophoresis was used to estimate quantitatively the levels of specific cross-reacting material in the derived lines. The results show that the variation in activity is due to differences in the amount of EST 6 present. The data are consistent with the hypothesis that there is at least one locus on the X chromosome that regulates the synthesis of EST 6 and that this regulatory locus may be polymorphic in natural populations.

A genetic analysis of path length and pupation height in a natural population of Drosophila melanogaster

1985 ◽  
Vol 27 (3) ◽  
pp. 334-340 ◽  
Author(s):  
Sharon J. Bauer ◽  
Marla B. Sokolowski
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Population ◽  
Path Length ◽  
Natural Populations ◽  
Culture Dish ◽  
Genetic Studies ◽  
The Third ◽  
Larval Behaviour ◽  
Pupation Height ◽  
Path Lengths

Behaviour–genetic studies using laboratory strains of Drosophila are often criticized because the results cannot be generalized to natural populations. The genetic component of variation in two prepupal behaviours was studied for strains derived from a natural population of Drosophila melanogaster. These strains showed a second-chromosome based contribution to differences in path length (the distance a larva crawls in a yeasted culture dish) with the long path length phenotype dominant over the short. Differences in pupation height (the distance a larva pupates above the surface of the medium) were affected not only by the second chromosomes but also by the third pair of chromosomes. The second pair influenced the differences in pupation height threefold more than the third. Intermediate pupation heights were found in the reciprocal crosses. While path lengths could be replicated in their absolute scores over different days, pupation heights could only be replicated in their relative scores.Key words: larval behaviour, Drosophila, natural population, genetics.

scholarly journals Opposing Modes of Selection on the Alcohol Dehydrogenase Locus in Drosophila Melanogaster

1980 ◽  
Vol 33 (1) ◽  
pp. 105 ◽  
Author(s):  
JG Oakeshott ◽  
JB Gibson ◽  
PR Anderson ◽  
A Champ
Keyword(s):  
Aqueous Solution ◽  
Drosophila Melanogaster ◽  
Alcohol Dehydrogenase ◽  
Dehydrogenase Activity ◽  
Natural Populations ◽  
Natural Environments ◽  
Experimental Conditions ◽  
The Third ◽  
Alcohol Dehydrogenase Activity ◽  
Survival Differences

Three experiments have been carried out which show that exogenous environments of ethanol impose selection on the alcohol dehydrogenase (Adh) locus of D. melanogaster. This locus is widely polymorphic for two alleles, AdhF and Adhs, and AdhF generally produces about twice as much alcohol dehydrogenase activity as Adhs. In the first experiment, AdhF IAdhF and AdhF/Adhs flies survived equally often and Adhs/Adhs flies less frequently after exposure for 7 days to medium impregnated with ethanol. The same pattern of survival differences was found in the second experiment in which flies were exposed for 1 day to an aqueous solution of ethanol and sucrose. In contrast, in the third experiment survival was scored after exposure for 45-min to ethanol fumes, and Adhs/ Adhs flies survived more often than AdhF/Adhs, both these genotypes surviving more frequently than Adh F / Adh F. We doubt whether anyone of the three experiments by itself adequately represents the ecology of natural populations of D. melanogaster exposed to ethanol. It is likely that mixtures of the three experimental conditions approximate more closely the natural environments and therefore we suggest that, overall, selection might favour intermediate levels of alcohol dehydrogenase activity, producing a net advantage for heterozygotes at the Adh locus.

INTERACTION IN TRANSMISSION FREQUENCY BETWEEN THE SECOND AND THE THIRD CHROMOSOMES IN DROSOPHILA MELANOGASTER

Genetics ◽  
1984 ◽  
Vol 106 (4) ◽  
pp. 669-677
Author(s):  
Yuichiro Hiraizumi
Keyword(s):  
New York ◽  
Drosophila Melanogaster ◽  
Natural Populations ◽  
Laboratory Strain ◽  
Isofemale Lines ◽  
The Third ◽  
Heterozygous Male ◽  
Mendelian Expectation ◽  
Group A ◽  
Group B

ABSTRACT Wild second and third chromosomes from isofemale lines established from wild-inseminated females captured in natural populations of Drosophila melanogaster in Hawaii, New York, North Carolina and Texas were made heterozygous in males with marked second and third chromosomes from a laboratory strain, and the transmission frequencies of the wild second (= k  2) and the third (= k  3) chromosomes from the heterozygous male parents were measured. Based upon the preliminary tests of k  2, the isofemale lines were classified into two groups; group A included those lines showing average k  2 values considerably smaller than the Mendelian expectation of 0.5, and group B included those lines showing average k  2 values close to 0.5. Effects of the wild second chromosomes on k  2 in group A were suppressed (the average k  2 values increased) by the presence of the wild third chromosomes, whereas the wild second chromosomes in this group, in turn, caused a decrease in k  3 of the wild third chromosomes. The intensities of the observed effects were more or less comparable in their absolute values, and these phenomena do not appear to be due to differential viabilities of zygotes. No such interaction was observed between the wild second and third chromosomes in group B. An extention of the model of the Segregation Distorter system of D. melanogaster, as well as a model based upon the P-M system of hybrid dysgenesis, may explain the observed results.

scholarly journals CHROMOSOME INTERACTIONS IN DROSOPHILA MELANOGASTER. II. TOTAL FITNESS

Genetics ◽  
1982 ◽  
Vol 102 (3) ◽  
pp. 485-502
Author(s):  
Robert D Seager ◽  
Francisco J Ayala ◽  
R William Marks
Keyword(s):  
Drosophila Melanogaster ◽  
Threshold Model ◽  
Fitness Function ◽  
Natural Populations ◽  
Genetic Load ◽  
Chromosome 2 ◽  
Synergistic Interactions ◽  
The Third ◽  
Mean Fitness ◽  
Selective Maintenance

ABSTRACT In a large experiment, using nearly 200 population cages, we have measured the fitness of Drosophila melanogaster homozygous (1) for the second chromosome, (2) for the third chromosome, and (3) for both chromosomes. Twentyfour second chromosomes and 24 third chromosomes sampled from a natural population were tested. The mean fitness of the homozygous flies is 0.081 ± 0.014 for the second chromosome, 0.080 ± 0.017 for the third chromosome, and 0.079 ± 0.024 for both chromosomes simultaneously. Assuming that fitnesses are multiplicative (the additive fitness model makes no sense in the present case because of the large selection coefficients involved), the expected mean fitness of the homozygotes for both chromosomes is 0.0066; their observed fitness is more than ten times greater. Thus, it appears that synergistic interactions between loci are considerable; and that, consequently, the fitness function substantially departs from linearity. Two models are tentatively suggested for the fitness function: a "threshold" model and a "synergistic" model.—The experiments reported here confirm previous results showing that the concealed genetic load present in natural populations of Drosophila is sufficient to account for the selective maintenance of numerous polymorphisms (of the order of 1000).

scholarly journals A Cluster of Cuticle Protein Genes of Drosophila melanogaster at 65A: Sequence, Structure and Evolution

Genetics ◽  
1997 ◽  
Vol 147 (3) ◽  
pp. 1213-1224
Author(s):  
Jean-Philippe Charles ◽  
Carol Chihara ◽  
Shamim Nejad ◽  
Lynn M Riddiford
Keyword(s):  
Drosophila Melanogaster ◽  
Genomic Dna ◽  
Multiple Copy ◽  
Sequence Structure ◽  
Coding Regions ◽  
The Third ◽  
Genetic Complexity ◽  
Genes Encoding ◽  
Cuticle Protein ◽  
Cuticle Proteins

A 36-kb genomic DNA segment of the Drosophila melanogaster genome containing 12 clustered cuticle genes has been mapped and partially sequenced. The cluster maps at 65A 5-6 on the left arm of the third chromosome, in agreement with the previously determined location of a putative cluster encompassing the genes for the third instar larval cuticle proteins LCP5, LCP6 and LCP8. This cluster is the largest cuticle gene cluster discovered to date and shows a number of surprising features that explain in part the genetic complexity of the LCP5, LCP6 and LCP8 loci. The genes encoding LCP5 and LCP8 are multiple copy genes and the presence of extensive similarity in their coding regions gives the first evidence for gene conversion in cuticle genes. In addition, five genes in the cluster are intronless. Four of these five have arisen by retroposition. The other genes in the cluster have a single intron located at an unusual location for insect cuticle genes.

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