scholarly journals STUDIES OF ESTERASE 6 IN DROSOPHILA MELANOGASTER. VI. EJACULATE COMPETITIVE ABILITIES OF MALES HAVING NULL OR ACTIVE ALLELES

Genetics ◽  
1981 ◽  
Vol 97 (1) ◽  
pp. 85-94 ◽  
Author(s):  
Donald G Gilbert ◽  
Rollin C Richmond
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Competitive Ability ◽  
Seminal Fluid ◽  
Experimental Conditions ◽  
Competition Mechanism ◽  
Esterase 6 ◽  
Significant Difference ◽  
Female Genotype ◽  
Male Genotype

ABSTRACT Recent studies of the function of the polymorphic seminal fluid enzyme, esterase 6, of Drosophila melanogaster suggested that it may act in the process of sperm displacement (Gilbert, Richmond and Sheehan, 1981a). This report examines the competitive ability of ejaculates from males homozygous for null or active alleles of esterase 6 under three experimental conditions that model aspects of sexual selection affecting males. The results demonstrate no significant difference in ejaculate competition between esterase 6 null or active male types, but marker males used for paternity identification had poorly competitive ejaculates. The proportion of second-male progeny, P  2, used as an index of competition is primarily influenced by second-male genotype and uninfluenced by female genotype. P2 can change with time from remating and be unaffected by different intensities of competition, which suggests a complex ejaculate competition mechanism.

scholarly journals IDENTIFICATION OF BRAIN SITES CONTROLLING FEMALE RECEPTIVITY IN MOSAICS OF DROSOPHILA MELANOGASTER

Genetics ◽  
1983 ◽  
Vol 103 (2) ◽  
pp. 179-195
Author(s):  
Laurie Tompkins ◽  
Jeffrey C Hall
Keyword(s):  
Drosophila Melanogaster ◽  
Minimum Amount ◽  
Male Courtship ◽  
Experimental Conditions ◽  
Female Receptivity ◽  
Female Genotype ◽  
Courtship Behaviors ◽  
Necessary And Sufficient ◽  
The Brain ◽  
Male Genotype

ABSTRACT We have identified cells in the brain of Drosophila melanogaster that are required to be of female genotype for receptivity to copulation with males. To do this, we determined experimental conditions in which female flies virtually always copulate, then measured the minimum amount of male courtship that is required to stimulate females to indicate their receptivity to copulation. We then observed gynandromorphs with female genitalia to determine whether the sex mosaics elicited at least the minimum amount of courtship and, if so, whether they copulated. By analyzing these gynandromorphs, in which the genotype of external and internal tissues could be ascertained, we were able to identify a group of cells in the dorsal anterior brain that, when bilaterally female, is necessary and sufficient for receptivity to copulation. This group of cells is anatomically distinct from those that are required to be of male genotype for the performance of courtship behaviors.

Molecular population genetics of structural variants of esterase 6 in Drosophila melanogaster

Genome ◽  
1989 ◽  
Vol 31 (2) ◽  
pp. 788-796 ◽  
Author(s):  
J. G. Oakeshott ◽  
P. H. Cooke ◽  
R. C. Richmond ◽  
A. Bortoli ◽  
A. Y. Game ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Amino Acid ◽  
Seminal Fluid ◽  
Biochemical Properties ◽  
Nucleotide Polymorphisms ◽  
Amino Acid Polymorphism ◽  
Sequence Comparisons ◽  
Esterase 6 ◽  
Latitudinal Clines

Several lines of evidence indicate that natural selection operates between the major EST6-F and EST6-S allozymes of Drosophila melanogaster. In particular, consistent latitudinal clines and seasonal variation in their relative frequencies strongly suggest that they are not selectively equivalent in field populations. Several laboratory studies have found frequency-dependent fitness differences among the Est6-F and Est6-S genotypes. Moreover, the purified EST6-F and EST6-S allozymes differ in biochemical properties and the physiology of the enzyme, as a major component of the seminal fluid, suggests that these differences could affect reproductive aspects of fitness. However, molecular analyses reveal high levels of variation in the EST6 protein both within and between the EST6-F and EST6-S allozymes. Limited thermostability and more sensitive electrophoretic analyses reveal at least 17 variants of the two allozymes and sequence comparisons among 13 isolates of the Est6 gene reveal 16 nucleotide polymorphisms that would lead to amino acid differences. Two closely linked amino acid differences are strongly associated with the major difference between EST6-F and EST6-S; either or both of these are likely to cause the observed biochemical differences between EST6-F and EST6-S and may be the primary targets for the selection between these allozymes. The functional and adaptive significance of the other amino acid polymorphisms is unclear, although the data suggest that the EST6-8 haplotype within EST6-S has both arisen and proliferated relatively recently.Key words: Drosophila melanogaster, esterase 6, nucleotide and amino acid polymorphism, natural selection.

Localization and longevity of seminal-fluid esterase 6 in mated female Drosophila melanogaster

1990 ◽  
Vol 36 (2) ◽  
pp. 93-101 ◽  
Author(s):  
Douglas B. Meikle ◽  
Kathy B. Sheehan ◽  
Debra M. Phillis ◽  
Rollin C. Richmond
Keyword(s):  
Drosophila Melanogaster ◽  
Seminal Fluid ◽  
Esterase 6 ◽  
Mated Female

scholarly journals Female Genetic Contributions to Sperm Competition in Drosophila melanogaster

Genetics ◽  
2019 ◽  
Vol 212 (3) ◽  
pp. 789-800 ◽  
Author(s):  
Dawn S. Chen ◽  
Sofie Y. N. Delbare ◽  
Simone L. White ◽  
Jessica Sitnik ◽  
Martik Chatterjee ◽  
...  
Keyword(s):  
Nervous System ◽  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Reproductive Tract ◽  
Seminal Fluid ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Link Type ◽  
Female Genotype ◽  
Mechanistic Basis

In many species, sperm can remain viable in the reproductive tract of a female well beyond the typical interval to remating. This creates an opportunity for sperm from different males to compete for oocyte fertilization inside the female’s reproductive tract. In Drosophila melanogaster, sperm characteristics and seminal fluid content affect male success in sperm competition. On the other hand, although genome-wide association studies (GWAS) have demonstrated that female genotype plays a role in sperm competition outcome as well, the biochemical, sensory, and physiological processes by which females detect and selectively use sperm from different males remain elusive. Here, we functionally tested 26 candidate genes implicated via a GWAS for their contribution to the female’s role in sperm competition, measured as changes in the relative success of the first male to mate (P1). Of these 26 candidates, we identified eight genes that affect P1 when knocked down in females, and showed that five of them do so when knocked down in the female nervous system. In particular, Rim knockdown in sensory pickpocket (ppk)+ neurons lowered P1, confirming previously published results, and a novel candidate, caup, lowered P1 when knocked down in octopaminergic Tdc2+ neurons. These results demonstrate that specific neurons in the female’s nervous system play a functional role in sperm competition and expand our understanding of the genetic, neuronal, and mechanistic basis of female responses to multiple matings. We propose that these neurons in females are used to sense, and integrate, signals from courtship or ejaculates, to modulate sperm competition outcome accordingly.

scholarly journals Sexual selection can partly explain low frequencies of Segregation Distorter alleles

2021 ◽  
Vol 288 (1959) ◽  
Author(s):  
Thomas A. Keaney ◽  
Therésa M. Jones ◽  
Luke Holman
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Theoretical Model ◽  
Competitive Ability ◽  
Natural Frequencies ◽  
Mendelian Inheritance ◽  
Wild Populations ◽  
Low Frequencies ◽  
Female Remating ◽  
Segregation Distorter

The Segregation Distorter ( SD ) allele found in Drosophila melanogaster distorts Mendelian inheritance in heterozygous males by causing developmental failure of non- SD spermatids, such that greater than 90% of the surviving sperm carry SD . This within-individual advantage should cause SD to fix, and yet SD is typically rare in wild populations. Here, we explore whether this paradox can be resolved by sexual selection, by testing if males carrying three different variants of SD suffer reduced pre- or post-copulatory reproductive success. We find that males carrying the SD allele are just as successful at securing matings as control males, but that one SD variant ( SD-5 ) reduces sperm competitive ability and increases the likelihood of female remating. We then used these results to inform a theoretical model; we found that sexual selection could limit SD to natural frequencies when sperm competitive ability and female remating rate equalled the values observed for SD-5 . However, sexual selection was unable to explain natural frequencies of the SD allele when the model was parameterized with the values found for two other SD variants, indicating that sexual selection alone is unlikely to explain the rarity of SD .

scholarly journals THE INFLUENCE OF SEXUAL AND LARVAL SELECTION ON THE MAINTENANCE OF POLYMORPHISM AT THE SEPIA LOCUS IN DROSOPHILA MELANOGASTER

Genetics ◽  
1980 ◽  
Vol 95 (3) ◽  
pp. 743-755
Author(s):  
D Anxolabehere
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Wild Strain ◽  
Selection Model ◽  
Male Mating ◽  
Population Cage ◽  
Female Genotype ◽  
Frequency Changes ◽  
Experimental Values ◽  
Larval Selection

ABSTRACT Sexual selection is measured between two strains of Drosophila melanogaster: a wild strain and a strain mutant at the sepia locus. Frequencydependent male mating was found to be successful, whereas the female genotype exerted no influence. The rarer the male genotype becomes, the greater is its mating success. A selection model is built for this behavior characteristic in which selection operates differently in the two sexes. The genetic consequencies of this model upon the maintenance of genetic polymorphism at the sepia locus are compared to experimental data from previous population cage studies. The fit obtained with this sexual selection model is compared to that of the larval selection model previously investigated. A model composed of both sexual and larval components of fitness is presented. The role that each major selection component is expected to play in experimental populations as the gene frequency changes is discussed. Sexual selection leads to an equilibrium level higher than larval selection, and the combined model is very close to the experimental values.

scholarly journals Female genetic contributions to sperm competition in Drosophila melanogaster

2018 ◽  
Author(s):  
Dawn S. Chen ◽  
Sofie Y.N. Delbare ◽  
Simone L. White ◽  
Jessica L. Sitnik ◽  
Martik Chatterjee ◽  
...  
Keyword(s):  
Nervous System ◽  
Drosophila Melanogaster ◽  
Sperm Competition ◽  
Reproductive Tract ◽  
Seminal Fluid ◽  
Association Studies ◽  
Genome Wide Association Studies ◽  
Physiological Processes ◽  
Female Genotype ◽  
Mechanistic Basis

In many species, sperm can remain viable in the reproductive tract of a female well beyond the typical interval to remating. This creates an opportunity for sperm from different males to compete for oocyte fertilization inside the female’s reproductive tract. In Drosophila melanogaster, sperm morphology and seminal fluid content affect male success in sperm competition. On the other hand, although genome-wide association studies (GWAS) have demonstrated that female genotype plays a role in sperm competition outcome as well, the biochemical, sensory and physiological processes by which females detect and selectively use sperm from different males remain elusive. Here, we functionally tested 27 candidate genes implicated via a GWAS for their contribution to the female’s role in sperm competition, measured as changes in the relative success of the first male to mate (P1). Of these 27 candidates, we identified eight genes that affect P1 when knocked down in females, and also showed that six of them do so when knocked down in the female nervous system. Two genes in particular, Rim and caup, lowered P1 when knocked down in sensory pickpocket (ppk)+ neurons and octopaminergic Tdc2+ neurons, respectively. These results establish a functional role for the female’s nervous system in the process of sperm competition and expand our understanding of the genetic, neuronal and mechanistic basis of female responses to multiple matings. We propose that through their nervous system, females actively assess male compatibility based on courtship or ejaculates and modulate sperm competition outcome accordingly.

scholarly journals The purging of deleterious mutations in simple and complex mating environments

2017 ◽  
Vol 13 (10) ◽  
pp. 20170518 ◽  
Author(s):  
Julie Colpitts ◽  
Darla Williscroft ◽  
Harmandeep Singh Sekhon ◽  
Howard D. Rundle
Keyword(s):  
Drosophila Melanogaster ◽  
Sexual Selection ◽  
Natural Selection ◽  
Experimental Evolution ◽  
The Other ◽  
Deleterious Mutations ◽  
Complex Environment ◽  
Net Benefit ◽  
Significant Difference ◽  
General Expectation

There is a general expectation that sexual selection should align with natural selection to aid the purging of deleterious mutations, yet experiments comparing purging under monogamy versus polygamy have provided mixed results. Recent studies suggest that this may be because the simplified mating environments used in these studies reduce the benefit of sexual selection through males and hamper natural selection through females by increasing costs associated with sexual conflict. To test the effect of the physical mating environment on purging, we use experimental evolution in Drosophila melanogaster to track the frequency of four separate deleterious mutations in replicate populations that experience polygamy under either a simple or structurally complex mating arena while controlling for arena size. Consistent with past results suggesting a greater net benefit of polygamy in a complex environment, two of the mutations were purged significantly faster in this environment. The other two mutations showed no significant difference between environments.

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