Ravi Mandla Rose Hills
A Genetic Basis for the Evolution and Regulation of Heart Rate
One of the fastest heart rates in the world belongs to one of the smallest mammals, the Etruscan Shrew. Only weighing around 1.8 grams, this animal has a heart rate of 1511 beats per minute (in comparison, human heart rates are around 80 beats per minute). In contrast, the blue whale has a heart rate of about 8 bpm. This phenomenon of heart rate scaling can consistently be found throughout the animal kingdom, with smaller organisms possessing a higher heart rate compared to that of larger animals, though little research has been done to explain why. However, previous research has indicated that activity of the ion channel HCN4 is closely correlated with heart rate. We believe the cis-regulatory elements determining HCN4 activity, enhancers, have changed during evolution to create these differential heart rates. My project aims to test this hypothesis, assaying the activity of a putative enhancer for HCN4, then using sequence analysis to determine if differences in heart rate can be correlated with differences in this enhancer sequence throughout the animal kingdom.