Date of Completion


Thesis Advisor(s)

Eric Schultz

Honors Major

Ecology and Evolutionary Biology


Ecology and Evolutionary Biology


To determine the role of intestinal aquaporin 1 (AQP1), a passive water absorption channel, in the evolution of osmoregulatory physiology, I examined the differential expression of intestinal AQP1 between anadromous and landlocked ecotype of alewife in response to seawater challenges. I cloned and sequenced AQP1 from intestinal tissue of the alewife, following which I quantified the relative expression of AQP1 in each ecotype using Real-Time qPCR. In response to an acute seawater (30ppt) challenge, the anadromous alewives showed an upregulation of intestinal AQP1, while the landlocked alewives did not show a significant increased in AQP1 expression. After acclimation to seawater over 14 days, the anadromous alewives maintained a higher level of intestinal AQP1 expression compared to the landlocked alewives. The reduced seawater response exhibited by the landlocked alewives provides evidence for osmoregulatory evolution towards a completely freshwater lifecycle through relaxed selection of intestinal AQP1 water absorption mechanisms.