Gene expression plasticity in response to rapid and extreme elevation changes in <i>Perdix hodgsoniae</i> (Tibetan Partridge)

Phenotypic plasticity is a vital biological process facilitating the persistence of organisms amid rapid environmental changes. Investigating the genetic basis of plastic traits necessitates transplantation experiments, but much of the existing research has focused on laboratory model systems. Transplant experiments in the wild may provide better understanding of how plasticity operates in the context of real-world challenges. However, performing transplantation experiments in non-model systems, such as birds, could be challenging. In this study, we aim to develop <i>Perdix hodgsoniae</i> (Tibetan Partridge) inhabiting the highlands of the Tibetan Plateau as a suitable system to study genetic basis underlying short-term plastic response to rapid changes in elevation. We did a first attempt of field-based transplantation experiment by exposing <i>P. hodgsoniae</i> individuals to extreme change in elevation from their native elevation (3,623 m) to a low elevation outside their natural distribution range (500 m). We compared changes in gene expression in these birds at different time points, pre-transplant (day 0), and post-transplant (days 3 and 22). The birds successfully survived transplantation and exhibited well-being after 22 days. We identified a total of 715 differentially expressed genes (DEGs) across these time points. Our analysis revealed a genome-wide decrease in expression following the transplantation, indicating that the birds possibly exhibited stress-induced transcriptional attenuation (SITA) because of the extreme change in elevation, suggesting a broader response at the transcriptional level, possibly as a mechanism to cope with extreme changes in the environment. Our analysis further suggested that heat stress posed an immediate challenge for the birds following the transplant, as we identified changes in expression in many genes associated with heat stress response. Our findings affirm the viability of conducting transplant experiments in the <i>P. hodgsoniae</i> and provides initial insights into gene expression changes associated with the plastic response to rapid changes in elevation in these birds.