A CHROMOSOMAL ANALYSIS OF EGG PRODUCTION AND ABDOMINAL CHAETA NUMBER IN DROSOPHILA MELANOGASTER

1969 ◽  
Vol 11 (3) ◽  
pp. 547-557 ◽  
Author(s):  
J. F. Kidwell
Keyword(s):  
Drosophila Melanogaster ◽  
Egg Production ◽  
Directional Selection ◽  
Chromosomal Analysis ◽  
Stabilizing Selection ◽  
Additive Effects ◽  
Epistatic Interactions ◽  
Isogenic Lines ◽  
Metric Traits

A marked-inversion-outcross technique was used to produce the 81 possible combinations of entire chromosomes (genotypes) resulting from crosses of two isogenic lines. Two metric traits, egg production during the 6th, 7th and 8th day and the number of chaeta on the fourth and fifth abdominal segments, were measured. Heterogeneity of within-genotype variance was found for both traits. There is some evidence of increasing variance with increasing homozygosity, bur it is not conclusive.Egg production is influenced largely by additive and dominance effects of chromosomes 2 and 3 and by epistatic interactions involving all four chromosomes. Chaeta number is determined largely by chromosomes with additive effects. For both traits, however, the three- and four-factor epistatic interactions contributed a real and important fraction of the total variance.The data are consistent with the view that egg production has been subjected to directional selection and that chaeta number has been subjected to stabilizing selection.

A NOTE ON KIDWELL'S CHROMOSOMAL ANALYSIS OF EGG PRODUCTION AND CHAETA NUMBER IN DROSOPHILA MELANOGASTER

1970 ◽  
Vol 12 (2) ◽  
pp. 356-358 ◽  
Author(s):  
P. Glaser ◽  
J. F. Kldwell
Keyword(s):  
Drosophila Melanogaster ◽  
Egg Production ◽  
Genetic Variance ◽  
Chromosomal Analysis ◽  
Epistatic Variance

An earlier paper (Kidwell, J.F., 1969, Can. J. Genet. Cytol 11: 547-557) has described partitioning of the genetic variance of egg production and chaeta number in Drosophila melanogaster, assuming equal frequencies of all chromosomes. Kidwell's data were analyzed again, and the new analyses were based on several panmictic populations with varying frequencies for each genotype. The importances of the several portions of the genetic variance were estimated for each population; several cases are presented. In most cases the ranges were substantial, especially those of the dominance and four-factor epistatic variances. The results of the present study generally support Kidwell's previous conclusions and suggest that epistatic variance should not routinely be assumed negligible.

scholarly journals An Analysis of Polygenes Affecting Wing Shape on Chromosome 3 in Drosophila melanogaster

Genetics ◽  
1999 ◽  
Vol 153 (2) ◽  
pp. 773-786 ◽  
Author(s):  
Kenneth Weber ◽  
Robert Eisman ◽  
Lisa Morey ◽  
April Patty ◽  
Joshua Sparks ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Transposable Elements ◽  
Wing Shape ◽  
The Other ◽  
Chromosome 3 ◽  
Additive Effects ◽  
Data Set ◽  
The Third ◽  
Isogenic Lines ◽  
Negative Interactions

AbstractLoci on the third chromosome of Drosophila melanogaster that affect an index of wing shape were mapped, using recombinant isogenic lines, with transposable elements as markers. Many genes with small subequal effects are dispersed along the whole chromosome. Their alleles act nearly additively in heterozygotes. They have small correlated effects on leg shape, but no detectable effects on halteres. Small negative net interactions occur over most of the chromosome. The data set of 519 recombinant isogenic lines can be explained reasonably well by two models. One model posits an indefinitely large number of loci with no interactions. The other model posits 11 loci with additive effects whose sum equals the total phenotypic range and with large positive and negative interactions that nearly cancel each other.

scholarly journals CORRELATIONS BETWEEN CHROMOSOME SEGMENTS AND FITNESS IN DROSOPHILA MELANOGASTER. I. THE X CHROMOSOME AND EGG PRODUCTION

Genetics ◽  
1977 ◽  
Vol 85 (4) ◽  
pp. 721-732
Author(s):  
William Chapco
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Egg Production ◽  
Position Effect ◽  
X Chromosomes ◽  
Heterozygous Condition ◽  
Coupling Phase ◽  
Isogenic Lines ◽  
Apparent Relationship ◽  
Chromosome Segments

ABSTRACT Unmarked segments within the X chromosomes of four different Drosophila melanogaster isogenic lines were assessed with respect to egg production. By making a series of crosses among original and derived recombinant lines, it was possible to estimate parameters representing additive, dominance and interaction effects of the segments. It was shown that whereas most of the segments were additive for egg production when homozygous, they all displayed dominance in the heterozygous condition. Two of the strains were characterized by intersegmental interaction. A possible position effect was detected for these same two strains, with flies in the coupling phase laying more eggs than those in the repulsion configuration. There was no apparent relationship between the number of eggs laid and the amount of heterozygosity within the X chromosome.

scholarly journals CORRELATIONS BETWEEN CHROMOSOME SEGMENTS AND FITNESS IN DROSOPHILA MELANOGASTER. II. THE X CHROMOSOME AND EGG VIABILITY

Genetics ◽  
1979 ◽  
Vol 92 (2) ◽  
pp. 595-601
Author(s):  
William Chapco
Keyword(s):  
Drosophila Melanogaster ◽  
X Chromosome ◽  
Egg Production ◽  
Egg Viability ◽  
X Chromosomes ◽  
Isogenic Lines ◽  
Chromosome Segments

ABSTRACT Unmarked segments within the X chromosomes of four different Drosophila melanogaster isogenic lines were assessed with respect to egg-to-adult viability. The results were compared with those of an earlier study involving egg production. All segments influence both traits, but to extents that are dependent upon the strains being compared. Segmental effects are also a function of the genetical background, which, in this case, constitutes material within the same chromowme. With respect to both traits, the segments are not necessarily parallel in their effects. A segment that increases fecundity, for example, may or may not augment viability. The possibility of manipulating chromosomal segments to improve "yield" in organisms is explored.

scholarly journals Epistatic interactions attenuate mutations affecting startle behaviour in Drosophila melanogaster

2009 ◽  
Vol 91 (6) ◽  
pp. 373-382 ◽  
Author(s):  
AKIHIKO YAMAMOTO ◽  
ROBERT R. H. ANHOLT ◽  
TRUDY F. C. MACKAY
Keyword(s):  
Drosophila Melanogaster ◽  
Complex Traits ◽  
Genetic Architecture ◽  
Quantitative Traits ◽  
Empirical Support ◽  
Genetic Network ◽  
Stabilizing Selection ◽  
Evolutionary Potential ◽  
Epistatic Interactions ◽  
Main Effects

SummaryEpistasis is an important feature of the genetic architecture of quantitative traits. Previously, we showed that startle-induced locomotor behaviour of Drosophila melanogaster, a critical survival trait, is highly polygenic and exhibits epistasis. Here, we characterize epistatic interactions among homozygous P-element mutations affecting startle-induced locomotion in the Canton-S isogenic background and in 21 wild-derived inbred genetic backgrounds. We find pervasive epistasis for pairwise combinations of homozygous P-element insertional mutations as well as for mutations in wild-derived backgrounds. In all cases, the direction of the epistatic effects is to suppress the mutant phenotypes. The magnitude of the epistatic interactions in wild-derived backgrounds is highly correlated with the magnitude of the main effects of mutations, leading to phenotypic robustness of the startle response in the face of deleterious mutations. There is variation in the magnitude of epistasis among the wild-derived genetic backgrounds, indicating evolutionary potential for enhancing or suppressing effects of single mutations. These results provide a partial glimpse of the complex genetic network underlying the genetic architecture of startle behaviour and provide empirical support for the hypothesis that suppressing epistasis is the mechanism underlying genetic canalization of traits under strong stabilizing selection. Widespread suppressing epistasis will lead to underestimates of the main effects of quantitative trait loci (QTLs) in mapping experiments when not explicitly accounted for. In addition, suppressing epistasis could lead to underestimates of mutational variation for quantitative traits and overestimates of the strength of stabilizing selection, which has implications for maintenance of variation of complex traits by mutation–selection balance.

scholarly journals Genetic Screens for Factors Involved in the Notum Bristle Loss of Interspecific Hybrids Between Drosophila melanogaster and D. simulans

Genetics ◽  
2000 ◽  
Vol 156 (1) ◽  
pp. 269-282
Author(s):  
Toshiyuki Takano-Shimizu
Keyword(s):  
Drosophila Melanogaster ◽  
Interspecific Cross ◽  
Species Variation ◽  
Genetic Screens ◽  
Pure Species ◽  
Epistatic Interactions ◽  
X Chromosomes ◽  
Powerful Means ◽  
Different Populations ◽  
Deficiency Screening

Abstract Interspecific cross is a powerful means to uncover hidden within- and between-species variation in populations. One example is a bristle loss phenotype of hybrids between Drosophila melanogaster and D. simulans, although both the pure species have exactly the same pattern of bristle formation on the notum. There exists a large amount of genetic variability in the simulans populations with respect to the number of missing bristles in hybrids, and the variation is largely attributable to simulans X chromosomes. Using nine molecular markers, I screened the simulans X chromosome for genetic factors that were responsible for the differences between a pair of simulans lines with high (H) and low (L) missing bristle numbers. Together with duplication-rescue experiments, a single major quantitative locus was mapped to a 13F–14F region. Importantly, this region accounted for most of the differences between H and L lines in three other independent pairs, suggesting segregation of H and L alleles at the single locus in different populations. Moreover, a deficiency screening uncovered several regions with factors that potentially cause the hybrid bristle loss due to epistatic interactions with the other factors.

Epistatic Interactions Between smell-impaired Loci in Drosophila melanogaster

Genetics ◽  
1998 ◽  
Vol 148 (4) ◽  
pp. 1885-1891 ◽  
Author(s):  
Grażyna M Fedorowicz ◽  
James D Fry ◽  
Robert R H Anholt ◽  
Trudy F C Mackay
Keyword(s):  
Drosophila Melanogaster ◽  
Significant Variation ◽  
P Element ◽  
Olfactory Behavior ◽  
Epistatic Interactions ◽  
Combining Abilities ◽  
Multiple Loci ◽  
Quantitative Genetic ◽  
Half Diallel ◽  
Diallel Design

Abstract Odor-guided behavior is a polygenic trait determined by the concerted expression of multiple loci. Previously, P-element mutagenesis was used to identify single P[lArB] insertions, in a common isogenic background, with homozygous effects on olfactory behavior. Here, we have crossed 12 lines with these smell impaired (smi) mutations in a half-diallel design (excluding homozygous parental genotypes and reciprocal crosses) to produce all possible 66 doubly heterozygous hybrids with P[lArB] insertions at two distinct locations. The olfactory behavior of the transheterozygous progeny was measured using an assay that quantified the avoidance response to the repellent odorant benzaldehyde. There was significant variation in general combining abilities of avoidance scores among the smi mutants, indicating variation in heterozygous effects. Further, there was significant variation among specific combining abilities of each cross, indicating dependencies of heterozygous effects on the smi locus genotypes, i.e., epistasis. Significant epistatic interactions were identified for nine transheterozygote genotypes, involving 10 of the 12 smi loci. Eight of these loci form an interacting ensemble of genes that modulate expression of the behavioral phenotype. These observations illustrate the power of quantitative genetic analyses to detect subtle phenotypic effects and point to an extensive network of epistatic interactions among genes in the olfactory subgenome.

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