Transcriptomic variation and plasticity in rufous-collared sparrows (Zonotrichia capensis) along an altitudinal...

Area of Science:

• Evolutionary biology
• Genomics
• Physiology

Background:

• High-altitude environments present challenges like hypoxia and thermal stress.
• Physiological acclimation to these stresses can lead to evolutionary adaptation.
• Understanding gene expression plasticity is crucial for adaptation studies.

Purpose of the Study:

• To investigate the role of functional genomic variation in physiological acclimation and adaptation.
• To examine transcriptomic profiles of rufous-collared sparrows along an altitudinal gradient.
• To assess gene expression plasticity in response to environmental changes.

Main Methods:

• Skeletal muscle transcriptomic profiling of sparrows at high (4100 m) and low (2000 m) altitudes.
• Gene ontology and network analyses to identify differentially expressed transcripts.
• A common garden experiment transferring birds to a low-altitude site (150 m).

Main Results:

• Nearly 200 unique transcripts were differentially expressed between high- and low-altitude populations in their native habitats.
• Key pathways involved included oxidative phosphorylation, protein biosynthesis, signal transduction, and oxidative stress response.
• None of the altitude-specific gene expression differences persisted in the common garden experiment.

Conclusions:

• Demonstrates substantial plasticity in gene expression related to hypoxia and cold compensation in rufous-collared sparrows.
• Suggests that gene expression plasticity mechanistically enables the species' broad altitudinal distribution.
• Highlights the importance of plasticity in adaptation to environmental stress in natural bird populations.