Temperature and Nutrition Shape Genetic Basis of Body Size and Trait Scaling Independently in Fruit Flies
A study using ~200 isogenic Drosophila melanogaster lineages found that the genetic basis of body size plasticity driven by temperature is largely independent from that driven by nutrition. Researchers measured wing and leg size across multiple environmental conditions and found no genetic correlation between thermal and nutritional plasticity for either trait. This suggests that predicting how organisms evolve in response to environmental variation may be more complex than previously assumed.
Researchers used approximately 200 isogenic Drosophila melanogaster lineages to investigate whether the genetic architecture underlying body size plasticity is shared across different environmental drivers — specifically developmental temperature and nutrition. They measured wing and leg size under nutritional and thermal treatments, estimating plasticity for each trait and the individual-level scaling relationship (ILSR) between wing and leg size. The study found extensive genetic variation in both thermal and nutritional plasticity, but critically, a lineage's thermal plasticity showed no genetic correlation with its nutritional plasticity for either wings or legs. Similarly, the slopes of thermal and nutritional wing-leg scaling relationships were genetically uncorrelated, and nutritional scaling slopes at one temperature did not predict those at another temperature. Despite this, the overall pattern of nutritional scaling was broadly conserved across temperatures. These findings indicate that the genetic architecture of size plasticity and morphological scaling is environment-specific, complicating predictions about how natural selection will shape developmental mechanisms in heterogeneous environments.
What's missing
The study is a preprint posted to bioRxiv and has not yet undergone peer review, so findings should be interpreted with caution. The study does not directly test fitness consequences of the observed genetic variation in plasticity, leaving open the question of how selection actually acts on these mechanisms in natural populations. Additionally, the range of nutritional and thermal treatments used may not fully capture the breadth of environmental variation organisms experience in the wild.
What different sources said
- bioRxivCenter
Scaling Across Environments: Temperature and nutrition independently shape the genetics of size plasticity and morphological scaling
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