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Highly polygenic variation in environmental perception determines dauer larvae formation in growing populations of Caenorhabditis elegans.

Green JW, Stastna JJ, Orbidans HE, Harvey SC - PLoS ONE (2014)

Bottom Line: We also show that food patch size affects both the ability to detect QTLs and estimates of effect size, and demonstrate that an allele of nath-10 affects dauer larvae formation in growing populations.These data indicate that QTLs affecting the number of dauer larvae at food exhaustion in growing populations of C. elegans are highly reproducible, and that nearly all can be explained by variation affecting dauer larvae formation in response to defined amounts of pheromone.This suggests that most variation in dauer larvae formation in growing populations is a consequence of variation in the perception of the food and pheromone environment (i.e. chemosensory variation) and in the integration of these cues.

View Article: PubMed Central - PubMed

Affiliation: Biomolecular Research Group, School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, United Kingdom.

ABSTRACT

Background: Determining how complex traits are genetically controlled is a requirement if we are to predict how they evolve and how they might respond to selection. This requires understanding how distinct, and often more simple, life history traits interact and change in response to environmental conditions. In order to begin addressing such issues, we have been analyzing the formation of the developmentally arrested dauer larvae of Caenorhabditis elegans under different conditions.

Results: We find that 18 of 22 previously identified quantitative trait loci (QTLs) affecting dauer larvae formation in growing populations, assayed by determining the number of dauer larvae present at food patch exhaustion, can be recovered under various environmental conditions. We also show that food patch size affects both the ability to detect QTLs and estimates of effect size, and demonstrate that an allele of nath-10 affects dauer larvae formation in growing populations. To investigate the component traits that affect dauer larvae formation in growing populations we map, using the same introgression lines, QTLs that affect dauer larvae formation in response to defined amounts of pheromone. This identifies 36 QTLs, again demonstrating the highly polygenic nature of the genetic variation underlying dauer larvae formation.

Conclusions: These data indicate that QTLs affecting the number of dauer larvae at food exhaustion in growing populations of C. elegans are highly reproducible, and that nearly all can be explained by variation affecting dauer larvae formation in response to defined amounts of pheromone. This suggests that most variation in dauer larvae formation in growing populations is a consequence of variation in the perception of the food and pheromone environment (i.e. chemosensory variation) and in the integration of these cues.

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Related in: MedlinePlus

Introgression lines vary in the number of dauer larvae present a week after food exhaustion.Box and whisker plots of the number of dauer larvae present a week after exhaustion of 100 µl of 20% w/v food in N2, CB4856 and in ILs containing both positive and negative effect QTLs. CB4856 is shown only as a reference. ILs that differed from N2 are indicated by asterisks above the line names (p<0.05, post hoc Mann-Whitney U-tests). IL versus IL comparisons are shown at the top of the figure, with asterisks denoting significant differences between ILs tested (p<0.05, Mann-Whitney U-tests with a Bonferroni adjustment to correct for multiple testing), comparisons where the ILs do not differ are labelled NS.
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pone-0112830-g002: Introgression lines vary in the number of dauer larvae present a week after food exhaustion.Box and whisker plots of the number of dauer larvae present a week after exhaustion of 100 µl of 20% w/v food in N2, CB4856 and in ILs containing both positive and negative effect QTLs. CB4856 is shown only as a reference. ILs that differed from N2 are indicated by asterisks above the line names (p<0.05, post hoc Mann-Whitney U-tests). IL versus IL comparisons are shown at the top of the figure, with asterisks denoting significant differences between ILs tested (p<0.05, Mann-Whitney U-tests with a Bonferroni adjustment to correct for multiple testing), comparisons where the ILs do not differ are labelled NS.

Mentions: Shown is the difference in dauer larvae number between the IL and N2 from that assay, or between two ILs, for two re-tests of ILs with introgressions on the X chromosome for the number of dauer larvae at food exhaustion (data from [28]), two assays for the number of dauer larvae at food exhaustion, and an assay of dauer larvae numbers a week after food exhaustion (see Figure 2). Values in bold are significantly different (post hoc comparison by Mann-Whitney U-test, p<0.05) in the relevant comparison (N2 vs IL or IL vs IL). ‘QTL effect’ indicates if the initial genome-wide screen identified the QTL as positive or negative, ‘Same sign’ shows if the difference is in the same direction in all tests at food exhaustion. ‘Support’ indicates in the assay of dauer larvae numbers a week after food exhaustion identified a QTL with the same effect as the original screen. Note that QTLs gp1 and 17 are detected in Figure 1.


Highly polygenic variation in environmental perception determines dauer larvae formation in growing populations of Caenorhabditis elegans.

Green JW, Stastna JJ, Orbidans HE, Harvey SC - PLoS ONE (2014)

Introgression lines vary in the number of dauer larvae present a week after food exhaustion.Box and whisker plots of the number of dauer larvae present a week after exhaustion of 100 µl of 20% w/v food in N2, CB4856 and in ILs containing both positive and negative effect QTLs. CB4856 is shown only as a reference. ILs that differed from N2 are indicated by asterisks above the line names (p<0.05, post hoc Mann-Whitney U-tests). IL versus IL comparisons are shown at the top of the figure, with asterisks denoting significant differences between ILs tested (p<0.05, Mann-Whitney U-tests with a Bonferroni adjustment to correct for multiple testing), comparisons where the ILs do not differ are labelled NS.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4231163&req=5

pone-0112830-g002: Introgression lines vary in the number of dauer larvae present a week after food exhaustion.Box and whisker plots of the number of dauer larvae present a week after exhaustion of 100 µl of 20% w/v food in N2, CB4856 and in ILs containing both positive and negative effect QTLs. CB4856 is shown only as a reference. ILs that differed from N2 are indicated by asterisks above the line names (p<0.05, post hoc Mann-Whitney U-tests). IL versus IL comparisons are shown at the top of the figure, with asterisks denoting significant differences between ILs tested (p<0.05, Mann-Whitney U-tests with a Bonferroni adjustment to correct for multiple testing), comparisons where the ILs do not differ are labelled NS.
Mentions: Shown is the difference in dauer larvae number between the IL and N2 from that assay, or between two ILs, for two re-tests of ILs with introgressions on the X chromosome for the number of dauer larvae at food exhaustion (data from [28]), two assays for the number of dauer larvae at food exhaustion, and an assay of dauer larvae numbers a week after food exhaustion (see Figure 2). Values in bold are significantly different (post hoc comparison by Mann-Whitney U-test, p<0.05) in the relevant comparison (N2 vs IL or IL vs IL). ‘QTL effect’ indicates if the initial genome-wide screen identified the QTL as positive or negative, ‘Same sign’ shows if the difference is in the same direction in all tests at food exhaustion. ‘Support’ indicates in the assay of dauer larvae numbers a week after food exhaustion identified a QTL with the same effect as the original screen. Note that QTLs gp1 and 17 are detected in Figure 1.

Bottom Line: We also show that food patch size affects both the ability to detect QTLs and estimates of effect size, and demonstrate that an allele of nath-10 affects dauer larvae formation in growing populations.These data indicate that QTLs affecting the number of dauer larvae at food exhaustion in growing populations of C. elegans are highly reproducible, and that nearly all can be explained by variation affecting dauer larvae formation in response to defined amounts of pheromone.This suggests that most variation in dauer larvae formation in growing populations is a consequence of variation in the perception of the food and pheromone environment (i.e. chemosensory variation) and in the integration of these cues.

View Article: PubMed Central - PubMed

Affiliation: Biomolecular Research Group, School of Human and Life Sciences, Canterbury Christ Church University, Canterbury, United Kingdom.

ABSTRACT

Background: Determining how complex traits are genetically controlled is a requirement if we are to predict how they evolve and how they might respond to selection. This requires understanding how distinct, and often more simple, life history traits interact and change in response to environmental conditions. In order to begin addressing such issues, we have been analyzing the formation of the developmentally arrested dauer larvae of Caenorhabditis elegans under different conditions.

Results: We find that 18 of 22 previously identified quantitative trait loci (QTLs) affecting dauer larvae formation in growing populations, assayed by determining the number of dauer larvae present at food patch exhaustion, can be recovered under various environmental conditions. We also show that food patch size affects both the ability to detect QTLs and estimates of effect size, and demonstrate that an allele of nath-10 affects dauer larvae formation in growing populations. To investigate the component traits that affect dauer larvae formation in growing populations we map, using the same introgression lines, QTLs that affect dauer larvae formation in response to defined amounts of pheromone. This identifies 36 QTLs, again demonstrating the highly polygenic nature of the genetic variation underlying dauer larvae formation.

Conclusions: These data indicate that QTLs affecting the number of dauer larvae at food exhaustion in growing populations of C. elegans are highly reproducible, and that nearly all can be explained by variation affecting dauer larvae formation in response to defined amounts of pheromone. This suggests that most variation in dauer larvae formation in growing populations is a consequence of variation in the perception of the food and pheromone environment (i.e. chemosensory variation) and in the integration of these cues.

Show MeSH
Related in: MedlinePlus