Cell-autonomous adaptations (CAAs) represent a significant class of evolutionary adjustments occurring at the cellular level in multicellular life forms. Unlike broader adaptations affecting tissues or systems, CAAs enhance individual cell functions. These adaptations arise from germline-inherited genetic alterations and respond to diverse environmental challenges. CAAs have functional parallels in unicellular organisms, illustrating their evolutionary universality.
Adaptation in human evolution
Environmental stresses have driven diverse adaptations in multicellular organisms, particularly humans, often involving both CAAs and systemic responses. For example, hypoxia has prompted adaptations in Sherpa’s mitochondria to demonstrate CAAs by enhancing oxygen use and minimizing oxidative strain. Also, cold climates pose challenges addressed through CAAs like cellular thermogenesis, linked to THADA gene in humans.
To identify novel CAAs, authors propose integrating genome-wide scans with targeted analysis based on cellular fitness, evolutionary preservation, and gene expression to distinguish CAAs from non-CAAs. Applying this framework to high-altitude Andean populations revealed HSP70, a stress-response gene, and GTF2H5, gene essential for DNA repair under UV strain, as potential CAAs.
In conclusion, CAAs represent a distinct evolutionary mechanism operating at the cellular level, highlighting the shared evolutionary history of unicellular and multicellular organisms. These adaptations, such as cellular thermogenesis, often manifest at both genetic and physiological levels, providing heritable and immediate responses to environmental challenges. The CAA framework not only enriches our understanding of adaptation and multicellularity but also offers practical avenues for genomic investigation and biomedical studies.
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