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Genetic background and GxE interactions modulate the penetrance of a naturally occurring wing mutation in Drosophila melanogaster.

Lachance J, Jung L, True JR - G3 (Bethesda) (2013)

Bottom Line: We found significant epistasis, genotype-by-environment interactions, and maternal effects.We also found evidence of naturally segregating suppressors of vesiculated.Taken together, these findings indicate that multiple genetic and environmental factors modulate the phenotypic effects of a naturally occurring vesiculated allele.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6145.

ABSTRACT
Many genes involved in producing complex traits are incompletely penetrant. One such example is vesiculated, an X-linked gene in Drosophila melanogaster that results in wing defects. To examine the genetic architecture of a complex trait (wings containing vesicles), we placed a naturally occurring variant into multiple autosomal backgrounds and quantified penetrance and expressivity at a range of developmental temperatures. We found significant epistasis, genotype-by-environment interactions, and maternal effects. Sex and temperature effects were modulated by genetic background. The severity of wing phenotypes also varied across different genetic backgrounds, and expressivity was positively correlated with penetrance. We also found evidence of naturally segregating suppressors of vesiculated. These suppressors were present on both the second and third chromosomes, and complex interactions were observed. Taken together, these findings indicate that multiple genetic and environmental factors modulate the phenotypic effects of a naturally occurring vesiculated allele.

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Expressivity of vesiculated in multiple genetic backgrounds. All flies tested have vs2214 X chromosomes. Phenotypic scores range from 0 (wild-type) to 3 (balloon-like wings). For each treatment, shading in each cell of a 4 × 4 grid indicates the proportion of flies with a particular combination of left and right wing scores. Shading ranges from white (0%) to black (>10%). For scores >10%, the percentage is also listed. (A) Expressivity data for males. (B) Expressivity data for females. Median number of flies per combination of treatments (sex, temperature, and autosomal background) is 213.
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fig4: Expressivity of vesiculated in multiple genetic backgrounds. All flies tested have vs2214 X chromosomes. Phenotypic scores range from 0 (wild-type) to 3 (balloon-like wings). For each treatment, shading in each cell of a 4 × 4 grid indicates the proportion of flies with a particular combination of left and right wing scores. Shading ranges from white (0%) to black (>10%). For scores >10%, the percentage is also listed. (A) Expressivity data for males. (B) Expressivity data for females. Median number of flies per combination of treatments (sex, temperature, and autosomal background) is 213.

Mentions: Sex, genetic background, and temperature can influence not only presence or absence of wing defects but also the severity of wing defects. We examined flies with vs2214 containing X chromosomes and quantified the severity of wing phenotypes for both sexes, four different autosomal backgrounds, and four different developmental temperatures. For each treatment, the proportion of flies with a particular combination of left and right wing scores is indicated with shading in Figure 4. Overall, autosomal background had a large effect on the severity of wing defects. Mean phenotypic scores varied by genetic background: 0.000 for 2214, 0.343 for 6326, 0.216 for Sudbury, and 0.647 for Rum Cay. Most flies with Sudbury or 6326 autosomes were wild type. In contrast, many flies with Rum Cay autosomes had wing vesicles, often in both wings. To a lesser extent, expressivity also varied by temperature (contrast rows and columns in Figure 4). Sex differences in the severity of wing phenotypes were minimal. Overall, there was no significant left-right asymmetry in the presence and magnitude of wing vesicles (p > 0.5, two sample Z-test). Also, the probability that one wing was defective was not independent of the probability that the other wing was defective (p < 0.00001, χ2 test of independence with 1 d.f.). We observed an overabundance of flies with both wings affected (4.49% compared with 1.57%, the product of left and right wing penetrance). This finding suggests that factors influencing the wing phenotypes of individual flies acted globally rather than locally.


Genetic background and GxE interactions modulate the penetrance of a naturally occurring wing mutation in Drosophila melanogaster.

Lachance J, Jung L, True JR - G3 (Bethesda) (2013)

Expressivity of vesiculated in multiple genetic backgrounds. All flies tested have vs2214 X chromosomes. Phenotypic scores range from 0 (wild-type) to 3 (balloon-like wings). For each treatment, shading in each cell of a 4 × 4 grid indicates the proportion of flies with a particular combination of left and right wing scores. Shading ranges from white (0%) to black (>10%). For scores >10%, the percentage is also listed. (A) Expressivity data for males. (B) Expressivity data for females. Median number of flies per combination of treatments (sex, temperature, and autosomal background) is 213.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3815054&req=5

fig4: Expressivity of vesiculated in multiple genetic backgrounds. All flies tested have vs2214 X chromosomes. Phenotypic scores range from 0 (wild-type) to 3 (balloon-like wings). For each treatment, shading in each cell of a 4 × 4 grid indicates the proportion of flies with a particular combination of left and right wing scores. Shading ranges from white (0%) to black (>10%). For scores >10%, the percentage is also listed. (A) Expressivity data for males. (B) Expressivity data for females. Median number of flies per combination of treatments (sex, temperature, and autosomal background) is 213.
Mentions: Sex, genetic background, and temperature can influence not only presence or absence of wing defects but also the severity of wing defects. We examined flies with vs2214 containing X chromosomes and quantified the severity of wing phenotypes for both sexes, four different autosomal backgrounds, and four different developmental temperatures. For each treatment, the proportion of flies with a particular combination of left and right wing scores is indicated with shading in Figure 4. Overall, autosomal background had a large effect on the severity of wing defects. Mean phenotypic scores varied by genetic background: 0.000 for 2214, 0.343 for 6326, 0.216 for Sudbury, and 0.647 for Rum Cay. Most flies with Sudbury or 6326 autosomes were wild type. In contrast, many flies with Rum Cay autosomes had wing vesicles, often in both wings. To a lesser extent, expressivity also varied by temperature (contrast rows and columns in Figure 4). Sex differences in the severity of wing phenotypes were minimal. Overall, there was no significant left-right asymmetry in the presence and magnitude of wing vesicles (p > 0.5, two sample Z-test). Also, the probability that one wing was defective was not independent of the probability that the other wing was defective (p < 0.00001, χ2 test of independence with 1 d.f.). We observed an overabundance of flies with both wings affected (4.49% compared with 1.57%, the product of left and right wing penetrance). This finding suggests that factors influencing the wing phenotypes of individual flies acted globally rather than locally.

Bottom Line: We found significant epistasis, genotype-by-environment interactions, and maternal effects.We also found evidence of naturally segregating suppressors of vesiculated.Taken together, these findings indicate that multiple genetic and environmental factors modulate the phenotypic effects of a naturally occurring vesiculated allele.

View Article: PubMed Central - PubMed

Affiliation: Department of Genetics, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6145.

ABSTRACT
Many genes involved in producing complex traits are incompletely penetrant. One such example is vesiculated, an X-linked gene in Drosophila melanogaster that results in wing defects. To examine the genetic architecture of a complex trait (wings containing vesicles), we placed a naturally occurring variant into multiple autosomal backgrounds and quantified penetrance and expressivity at a range of developmental temperatures. We found significant epistasis, genotype-by-environment interactions, and maternal effects. Sex and temperature effects were modulated by genetic background. The severity of wing phenotypes also varied across different genetic backgrounds, and expressivity was positively correlated with penetrance. We also found evidence of naturally segregating suppressors of vesiculated. These suppressors were present on both the second and third chromosomes, and complex interactions were observed. Taken together, these findings indicate that multiple genetic and environmental factors modulate the phenotypic effects of a naturally occurring vesiculated allele.

Show MeSH
Related in: MedlinePlus