Condition dependence and the nature of genetic variation for male sex comb bristle number in Drosophila melanogaster

Genetica ◽  
2011 ◽  
Vol 139 (4) ◽  
pp. 505-510 ◽  
Author(s):  
Abha Ahuja ◽  
Scott De Vito ◽  
Rama S. Singh
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Condition Dependence ◽  
Bristle Number ◽  
Sex Comb ◽  
Male Sex

scholarly journals Genetic analysis of an intersex allele (ix5) that regulates sexual phenotype of both female and male Drosophila melanogaster

2002 ◽  
Vol 80 (1) ◽  
pp. 7-14 ◽  
Author(s):  
M. ACHARYYA ◽  
R. N. CHATTERJEE
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Analysis ◽  
Sex Determination ◽  
Male Genitalia ◽  
Point Mutations ◽  
Normal Male ◽  
Sexual Phenotype ◽  
Sex Comb ◽  
Male Sex ◽  
Courtship Activity

An allele of intersex (ix5) of Drosophila melanogaster has been characterized. The genetic analysis of the allele demonstrated that like other point mutations of ix, the ix5 allele also transformed diplo-X individuals into intersexes. The ix5 mutation also affects the arrangement of sex comb bristles on the forelegs of males, although they had morphologically nearly normal male genitalia. They often fail to display a sustained pattern of courtship activity when tested. Orcein-stained squash preparations of testes from ix5 males revealed a defect in spermatogenesis. Our results, taken together with those of McRobert & Tompkins (1985), indicate that the ix+ gene also functions in male sex determination.

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 Effects of Artificial Selection on Rates of Inbreeding in Populations of Drosophila Melanogaster

1969 ◽  
Vol 22 (1) ◽  
pp. 157 ◽  
Author(s):  
LP Jones
Keyword(s):  
Drosophila Melanogaster ◽  
Genetic Variation ◽  
Population Size ◽  
Effective Population Size ◽  
Artificial Selection ◽  
Selection Intensity ◽  
Base Population ◽  
Next Generation ◽  
Effective Population ◽  
Bristle Number

Three lines from the Canberra base population were selected for increased abdominal bristle number for up to 28 generations with 10 pairs of parents and 20% selection intensity. The effective population size as measured by either variance of family contributions to the next generation or by the rate of inbreeding was gener-ally lowest when the lines were responding rapidly to selection. Consideration of the contributions of families in any generation to the lines five generations later showed that much of the genetic variation came from only few families in some generations.

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 expression of additive and nonadditive genetic variation under stress.

Genetics ◽  
1995 ◽  
Vol 140 (3) ◽  
pp. 1149-1159
Author(s):  
M W Blows ◽  
M B Sokolowski
Keyword(s):  
Genetic Variation ◽  
Development Time ◽  
Genetic Effects ◽  
Hybrid Breakdown ◽  
Bristle Number ◽  
Gene Complexes ◽  
General Expectation ◽  
Faster Development ◽  
Seven Generations ◽  
Additive Genetic Effects

Abstract Experimental lines of Drosophila melanogaster derived from a natural population, which had been isolated in the laboratory for approximately 70 generations, were crossed to determine if the expression of additive, dominance and epistatic genetic variation in development time and viability was associated with the environment. No association was found between the level of additive genetic effects and environmental value for either trait, but nonadditive genetic effects increased at both extremes of the environmental range for development time. The expression of high levels of dominance and epistatic genetic variation at environmental extremes may be a general expectation for some traits. The disruption of the epistatic gene complexes in the parental lines resulted in hybrid breakdown toward faster development and there was some indication of hybrid breakdown toward higher viability. A combination of genetic drift and natural selection had therefore resulted in different epistatic gene complexes being selected after approximately 70 generations from a common genetic base. After crossing, the hybrid populations were observed for 10 generations. Epistasis contributed on average 12 hr in development time. Fluctuating asymmetry in sternopleural bristle number also evolved in the hybrid populations, decreasing by > 18% in the first seven generations after hybridization.

scholarly journals Hybrid dysgenesis-induced quantitative variation on the X chromosome of Drosophila melanogaster.

Genetics ◽  
1990 ◽  
Vol 124 (3) ◽  
pp. 627-636
Author(s):  
C Q Lai ◽  
T F Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Quantitative Traits ◽  
Natural Populations ◽  
Quantitative Variation ◽  
Hybrid Dysgenesis ◽  
X Chromosomes ◽  
Bristle Number ◽  
Seven Generations ◽  
Polygenic Variation

Abstract To determine the ability of the P-M hybrid dysgenesis system of Drosophila melanogaster to generate mutations affecting quantitative traits, X chromosome lines were constructed in which replicates of isogenic M and P strain X chromosomes were exposed to a dysgenic cross, a nondysgenic cross, or a control cross, and recovered in common autosomal backgrounds. Mutational heritabilities of abdominal and sternopleural bristle score were in general exceptionally high-of the same magnitude as heritabilities of these traits in natural populations. P strain chromosomes were eight times more mutable than M strain chromosomes, and dysgenic crosses three times more effective than nondysgenic crosses in inducing polygenic variation. However, mutational heritabilities of the bristle traits were appreciable for P strain chromosomes passed through one nondysgenic cross, and for M strain chromosomes backcrossed for seven generations to inbred P strain females, a result consistent with previous observations on mutations affecting quantitative traits arising from nondysgenic crosses. The new variation resulting from one generation of mutagenesis was caused by a few lines with large effects on bristle score, and all mutations reduced bristle number.

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