Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/150102

Maternal loading of a small heat shock protein increases embryo thermal tolerance in Drosophila melanogaster

Lockwood, B. L.·Julick, C. R.·Montooth, K. L.
View original source ↗Export metadata ↓

Abstract

Maternal investment is likely to have direct effects on offspring survival. In oviparous animals whose embryos are exposed to the external environment, maternal provisioning of molecular factors like mRNAs and proteins may help embryos cope with sudden changes in the environment. Here we sought to modify the maternal mRNA contribution to offspring embryos and test for maternal effects on acute thermal tolerance in early embryos of Drosophila melanogaster. We drove in vivo overexpression of a small heat shock protein gene (Hsp23) in female ovaries and measured the effects of acute thermal stress on offspring embryonic survival and larval development. We report that overexpression of the Hsp23 gene in female ovaries produced offspring embryos with increased thermal tolerance. We also found that brief heat stress in the early embryonic stage (0 to 1 hour-old) caused decreased larval performance later in life (5 to 10 days-old), as indexed by pupation height, as well as increased development time to pupation. Maternal overexpression of Hsp23 protected embryos against these heat-induced larval defects. Our data demonstrate that transient products of single genes have large and lasting effects on whole-organism environmental tolerance. Further, our results suggest that maternal effects have a profound impact on offspring survival in the context of thermal variability.\n\nSUMMARY STATEMENTA gene-specific maternal effect confers thermal tolerance to offspring embryos in the fruit fly Drosophila melanogaster.

Source connections

Explore related subjects

evolutionary biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Lockwood, B. L., Julick, C. R., Montooth, K. L.. 2017-06-14. Maternal loading of a small heat shock protein increases embryo thermal tolerance in Drosophila melanogaster. https://doi.org/10.1101/150102

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

Efficient growth factor production stabilizes cooperation in a cellular public goods game

Eukaryotic cells secrete growth factors that facilitate the proliferation and survival of neighboring cells in a coordinated manner essential for tissue development, repair, and homeostasis. However, mutant cells that fail to produce these factors may exploit the benefits provided by neighboring producers, thereby gaining a proliferative advantage that could lead to the extinction of the producer clone. Evolutionary theory predicts that preventing this "tragedy of the commons" requires a fixed spatial structure or other mechanisms that enable cells to interact preferentially with copies of themselves. Contrary to this expectation, we found that, in competition experiments, cells producing the diffusible growth factor interleukin-3 (IL3) resist invasion by non-producing mutant cells even in well-mixed populations, and that non-producers are driven to extinction instead. Using evolutionary game theory, we show that this outcome arises when the cost-to-benefit ratio of growth factor production falls below a critical threshold. We derive this tipping point analytically across the full parameter space of benefit function shape and group size and confirm that IL3 production in our experimental system satisfies this condition with a production cost less than 0.1% of the benefit conferred. These results demonstrate that efficient public good production alone can resolve the tragedy of the commons in populations of cells, and potentially in other biological systems.

evolutionary biology↗
bioRxiv2026

Repeated Transitions in Migratory Behavior Across a Songbird Radiation Are Not Driven by Selection on Shared Variation in Candidate Genes

Understanding the mechanisms facilitating the repeated evolution of traits is a core question in evolutionary biology. While repeated evolution has been observed across many systems, behavioral phenotypes have been less well studied than morphological traits. Migration is a behavioral adaptation to seasonality that has evolved independently in many animals, and repeated gains and losses of migratory behavior have been especially prevalent throughout the diversification of birds. While migratory traits are heritable in many taxa and candidate genes underlying intraspecific variation in migratory behavior have been identified, whether similar genetic changes are responsible for the repeated evolution of migration remains poorly understood. We used a phylogenomic approach to investigate the relationship between variation in candidate genes and migratory propensity across nearly all species in the parulid warbler radiation (n = 101), a group of songbirds in which migratory behavior has been lost and gained multiple times. Comparisons of candidate gene tree topologies to the parulid warbler species tree revealed cases of discordance, though these were explained by differences in the number of phylogenetically informative sites among genes rather than by elevated genetic similarity among species sharing migratory strategies. Testing models of coding sequence evolution identified sites with elevated dN/dS in five candidate genes, suggestive of positive selection; however, variation at these sites showed no clear association with migratory strategy, nor did we detect recurrent selection across lineages where transitions in migratory behavior most likely occurred. Together, these results contradict the hypothesis that selection on shared variation (ancestral polymorphisms or introgressed alleles) facilitated the repeated evolution of migration in this clade.

evolutionary biology↗
bioRxiv2026

Why development time matters: temperature influences plasticity while nutritional stress reshapes selection and evolutionary potential

The time it takes organisms to reach adulthood is often considered a central life-history trait that influences fitness and is highly plastic across environments. Despite its importance, direct estimates of how selection on development time varies across combinations of environmental stressors remain rare, limiting our understanding of its role in population responses to environmental change. We reared 68 full-sibling families of the vinegar fly, Drosophila melanogaster, at two temperatures (14{degrees}C and 28{degrees}C) on two diets (standard and low-calorie), and measured development time, body size (mass and wing size), egg-to-adult viability and productivity (number of offspring). Temperature caused the largest plastic response, with development taking 4-5 times longer at 14{degrees}C, whereas the low-calorie diet extended development by 20-30%. Yet diet, not temperature, changed directional selection on development time. On the standard diet, faster development was associated with higher fitness at both temperatures. On the low-calorie diet, this advantage disappeared, and at 14{degrees}C slower-developing females tended to produce more offspring. Viability selection showed consistent patterns. The low-calorie diet also increased evolvability in development time c.10-16-fold at both temperatures, and genetic correlations between diets were close to zero, indicating strong genotype-by-environment interactions. Plasticity in development time was not associated with fitness in any treatment. Overall, we provide evidence that development time is a functional trait whose relationship with fitness depends on the environment. Nutritional stress induced a smaller plastic response in development time than temperature, but had a larger effect on directional selection and evolvability. The stressor causing the greatest plastic change in a functional trait is therefore not necessarily the one that shapes its selection and evolution.

evolutionary biology↗