Genotype-specific developmental plasticity shapes the timing and robustness of reproductive capacity in Caenorhabditis elegans

Abstract

The effects of environmental stress on developmental phenotypes allows us to observe the adaptive capacity of various genotypes. In single-genotype populations, this allows for observing the effects of standing variation on the process of developmental plasticity. Typically, such efforts do not allow us to distinguish the effect of genotype from the effects of environment. In the Nematode Caenorhabditis elegans, however, the L1 stage of development allows for precise and controlled imposition of starvation on a synchronized population of individuals. This allows for systematic comparisons within and between defined genotypes.

This study provides a number of innovations in the study of Nematode developmental plasticity. The first is to demonstrate systems-level mechanisms of adaptive response for various genetic mutant phenotypes to extended L1 arrest. The effects of developmental deprivation are quantifiable by applying statistical modeling techniques to reproductive time-series. This is characterized for both a wildtype strain (N2) and a host of genetic mutant strains. A further contribution is investigating the effects of starvation at multi-generational timescales. This includes both two generations post-starvation and multiple starvation experiences with selection for fecundity over 11 generations.

Statistical techniques such as Kernel Density Estimation (KDE), fold-change analysis, and Area Under the Curve (AUC) analysis reveal differences from baseline in the form of shifts in reproductive timing and kurtosis in peak reproductive capacity characterize adaptive responses that are semi-independent of environment. Extending these patterns of response to ad hoc comparisons with multi-generational contexts reveals that different genotypes characterized by mutations of specific genetic loci lead to vastly different outcomes.