Fig 1.
Dose-response curves for survival of adult AIP flies exposed to lead acetate (top panels) or cadmium chloride (bottom panels).
Fig 2.
Extreme QTL mapping for variation in resistance to lead and cadmium exposure of adult flies.
Manhattan plots show all SNPs significantly associated with resistance to lead or cadmium exposure at FDR<0.05. The X-axis designates the chromosomal arms of the Drosophila genome. SNPs are color coded. Blue dots indicate SNPs in or near a gene that harbors multiple significant SNPs (≥5), green dots indicate SNPs with large allele frequency differences between the resistant population and the control population (≥2 fold), and red dots indicate SNPs with large allele frequency differences in or near a gene that harbors multiple significant SNPs(≥5). The horizontal dashed lines indicate the Bonferroni-corrected threshold for statistical significance.
Table 1.
SNPs and candidate genes associated with resistance to lead and cadmium exposure from extreme QTL analyses that passed the Bonferroni-corrected threshold (P < 1.896 x 10−8).
Fig 3.
Functional analyses of candidate genes associated with resistance following lead and cadmium exposure of adult flies.
The bar graphs represent differences between the number of flies alive for Mi{ET1} mutants (panels A and B) or RNAi lines (panels C and D) and their corresponding controls on the fifth day of exposure to lead (panels A and C) or cadmium (panels B and D). Bars above the horizontal line indicate increased susceptibility to heavy metal exposure, whereas bars below the horizontal line indicate increased resistance. Red bars indicate females and blue bars indicate males. Error bars denote standard errors. P-values are from the reduced ANOVA model. **: P<0.01, *: P<0.05.
Fig 4.
Networks associated with lead and cadmium susceptibility, based on known interactions between candidate genes in common among different exposure conditions.
(A) Interactions between candidate genes associated with both female and male resistance to lead exposure. (B) Interactions between candidate genes associated with both female and male resistance to cadmium exposure. (C) Interactions between candidate genes associated with resistance to both lead and cadmium exposure in males. (D) Interactions between candidate genes associated with resistance to both lead and cadmium exposure in females. Orange edges indicate physical interactions and green edges indicate genetic interactions. Purple circles indicate genes annotated with divalent ion binding functions. Yellow circles indicate genes tested and functionally validated through mutational analysis. The red circle indicates a gene annotated with divalent ion binding function and validated through mutational analysis.
Fig 5.
Networks derived from all candidate genes associated with heavy metal resistance that were in common between males and females or between lead and cadmium.
Orange edges indicate physical interactions and green edges indicate genetic interactions.
Table 2.
Biological function annotations of hub genes from human orthologous networks.
Fig 6.
Network of human candidate genes orthologous to the Drosophila candidate genes shown in Fig 5.
Orange edges indicate physical interactions and the green edge indicates a genetic interaction.
Fig 7.
Functional analyses of candidate hub genes with human orthologs associated with resistance to lead and cadmium exposure of adult flies using RNAi targeted knockdown of gene expression.
The bar graphs represent differences between the number of flies alive for RNAi lines and their corresponding controls on the seventh day of exposure to lead (A) or on the fifth day of exposure to cadmium (B). Bars above the horizontal line indicate increased susceptibility to heavy metal exposure, whereas bars below the horizontal line indicate increased resistance. Red bars indicate females and blue bars indicate males. Error bars denote standard errors. P-values are from the reduced ANOVA model. **: P<0.01, *: P<0.05. See also S11 Table.