scholarly journals GENETIC VARIATION AND GENETIC LOAD DUE TO THE MALE REPRODUCTIVE COMPONENT OF FITNESS IN DROSOPHILA

Genetics ◽  
1981 ◽  
Vol 97 (3-4) ◽  
pp. 719-730
Author(s):  
John G Brittnacher
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Female Choice ◽  
Genetic Load ◽  
Competition Experiment ◽  
Male Mating ◽  
Mating Competition ◽  
Mating Propensity ◽  
The Mean ◽  
Male Mating Competition

ABSTRACT The genetic variation and genetic load due to virility, the male reproductive component of fitness, was measured in Drosophila melanogaster and D. pseudoobscura using males homozygous and heterozygous for the second chromosome of each species. Virility was determined in a female-choice, male mating competition experiment where both mating propensity and fertility were taken into account.——The mean virility of the homozygous D. melanogaster males relative to the heterozygous males was 0.50; the relative mean virility of the quasinormal homozygotes was 0.56. The mean virility of the homozygous D. pseudoobscura males relative to the heterozygous males was 0.70; the relative mean virility of the nonsterile homozygotes was 0.72, and of the quasinormal homozygotes, 0.68.——Depending on the species and chromosome sampled, fertile homozygous males had a mean virility 15 to 50% lower than the mean viability of individuals homozygous for a chromosome with quasinormal viability. The genetic load due to virility was also greater than that due to the female reproductive component. This higher level of hidden genetic variation (or genetic load) indicates that the results of PROUT(1971a, b) and BUNDGAARD and CHRISTIANSEN(1972), where the virility component of fitness dominated the dynamics of an artificial polymorphism, may be more general and that virility may dominate the dynamics of natural polymorphisms as well.

scholarly journals GENETIC LOAD IN NATURAL POPULATIONS: IS IT COMPATIBLE WITH THE HYPOTHESIS THAT MANY POLYMORPHISMS ARE MAINTAINED BY NATURAL SELECTION?

Genetics ◽  
1974 ◽  
Vol 77 (3) ◽  
pp. 569-589
Author(s):  
Martin L Tracey ◽  
Francisco J Ayala
Keyword(s):  
Drosophila Melanogaster ◽  
Natural Selection ◽  
Natural Population ◽  
Natural Populations ◽  
Genetic Load ◽  
Structural Genes ◽  
Invertebrate Species ◽  
Average Proportion ◽  
Mean Fitness ◽  
The Mean

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.

The capacity for additional matings does not affect male mating competition in the sand goby

2006 ◽  
Vol 71 (4) ◽  
pp. 865-870 ◽  
Author(s):  
Andreas Nyman ◽  
Charlotta Kvarnemo ◽  
Ola Svensson
Keyword(s):  
Male Mating ◽  
Sand Goby ◽  
Mating Competition ◽  
Male Mating Competition

An Evolutionary Psychological Perspective of Indirect Aggression in Girls and Women

2018 ◽  
Author(s):  
Tracy Vaillancourt ◽  
Jaimie Arona Krems
Keyword(s):  
Social Status ◽  
Physical Attractiveness ◽  
Indirect Aggression ◽  
Male Mating ◽  
Psychological Perspective ◽  
Mating Competition ◽  
Intrasexual Aggression ◽  
Male Mating Competition ◽  
To Receive ◽  
High Social Status

Although the effects of sexual selection on male mating competition and intrasexual aggression have been studied extensively for well over a century, female mating competition and intrasexual aggression have only begun to receive serious attention in recent decades. Here, we focus on one aspect of sexually selected competition in girls and women—rival derogation, which takes the form of indirect aggression. We argue that this tactic of intrasexual competition both reduces a rival’s ability to compete for desirable mates and helps aggressors achieve and maintain their own high social status. We further argue that physical attractiveness initiates the pathway leading to high social status, which is preserved through the use of indirect aggression and is associated with increased dating and sexual behavior.

scholarly journals Selection for a threshold character in Drosophila: III. Genetic control of variability in plateaued populations

1970 ◽  
Vol 15 (3) ◽  
pp. 285-300 ◽  
Author(s):  
B. D. H. Latter
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Developmental Regulation ◽  
Allocation Of Resources ◽  
Genetic Changes ◽  
Domestic Species ◽  
Threshold Character ◽  
Bristle Number ◽  
The Mean ◽  
Selection For

SUMMARYAn analysis of populations of Drosophila melanogaster which had ceased to respond to selection for increased scutellar bristle number has disclosed the existence of an overall negative genetic correlation between replicate lines in the frequency of the two major component bristle types, viz. anteriors and posteriors. Negative phenotypic correlations among component bristle sites have also been detected within populations. A model involving competition among sites for the available resources of a particular limiting substrate is therefore proposed. Genetic changes have been effected in exceptional populations which lead either to an increase in the rate of production of the limiting substrate, or to a lowering of the concentration of the substrate necessary for bristle initiation. The allelic substitutions concerned are recessive, and have been described as decanalizing alleles in view of their effects on both bristle number variability and a measure of developmental regulation at individual anterior sites. Genetic variation has also been demonstrated for the mean allocation of resources to each of the four component bristle types, viz. anteriore interstitials, posteriors and apicals. A brief discussion is given of the implications of the model for breeding practice in domestic species.

scholarly journals THE EFFECT OF INBREEDING ON COMPETITIVE MALE-MATING ABILITY IN DROSOPHILA MELANOGASTER

Genetics ◽  
1984 ◽  
Vol 106 (4) ◽  
pp. 601-612
Author(s):  
Paul M Sharp
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Sexual Selection ◽  
Strong Influence ◽  
Inbred Lines ◽  
Male Mating ◽  
Male Body ◽  
Mating Ability ◽  
Sib Mating ◽  
The Difference

ABSTRACT The effect of full-sib inbreeding on competitive male-mating ability (CI♂) in Drosophila melanogaster was investigated in two experiments. In the first, five inbred lines (with reserves) were assessed up to 18 generations. Linear inbreeding depression, of 5.9% per 10% increase in homozygosity, was observed. In a second experiment, 21 inbred lines were tested after three generations of full-sib mating (without reserves), and the decline with inbreeding was more severe, the male competitive index (CI♂) decreasing by 10.7% per 10% increase in F. The difference between these results is attributed to natural selection acting on variation within the inbred lines in extent of homozygosity, which can arise because of the peculiarly strong influence of linkage in Drosophila. Furthermore, differentiation between the lines may have reflected this variation rather than the various effects of different alleles fixed.—These results imply that the genetic variation in male-mating ability is largely due to dominance (no epistasis was detected) and are consonant with the proposition that intermale sexual selection is a very important component of fitness in D. melanogaster. There was no evidence of a positive correlation between male body size and competitive mating ability.

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