Phenotypic Plasticity in the Lungs of Deer Mice (Peromyscus maniculatus) at High Altitude and the Relationship With Aerobic Performance
The importance of phenotypic plasticity during post developmental acclimation to high altitude has been recognized in the recent years. However, the relationship between morphological changes observed in the lungs resulting from this acclimation process and changes in aerobic performance at high altitude have not been sufficiently investigated. This thesis attempts to elucidate the specific morphological changes associated with changes in the lungs of adult deer mice acclimated to high altitude, and also to discern whether or not there is a relationship between aerobic performance and lung morphology at high altitude. Thus far the results show that adult deer mice have significantly greater surface area of the alveoli, and that this change seems to be the result of hypertrophy of existing alveolar tissue, as opposed to de novo alveolarization. This work also demonstrates that lung volume in deer mice is positively correlated with aerobic performance under hypoxic conditions, suggesting that the increase in lung mass of high altitude acclimated deer mice is beneficial to aerobic performance. However, this relationship is dependent on heart mass such that mice with greater heart mass receive a greater benefit from possessing larger lungs. This work highlights the importance of phenotypic changes in the lungs resulting from acclimation to high altitude.