Date of Award

Spring 4-12-2019

Document Type


Degree Name

Master of Arts (MA)



First Advisor

Michael E. Steiper

Second Advisor

Herman Pontzer

Academic Program Adviser

Leo Coleman


The endurance running hypothesis has emerged as a key idea to explain several unique anatomical, physiological, and genetic features of modern humans—among these features is the evolution of ACTN3 (Bramble & Lieberman 2004, Nature), a gene linked to human athletic performance. An additional gene linked to human endurance performance is ACE. Because endurance running is a uniquely human trait, I predicted that ACE and ACTN3 genes would be evolving adaptively in the human lineage when examined in a wider primatological framework. To test this I compiled ACE and ACTN3 genes from 14 primate species and phylogenetically tested if these genes had a significantly different pattern of selection in the human lineage compared to other primates. I found that the human lineage experienced significantly weaker purifying selection in ACTN3 when compared to other primate lineages. The human ACE gene, on the other hand, was not evolving differently. Thus, these results show that there has been negative purifying selection acting on both genes for all primate species. However, ACTN3 is evolving differentially in humans than other primates and has a relatively elevated rate of amino acid replacements compared to other primates. Further research is required to study the amino acid replacements found in the human ACTN3 gene to determine if any play a role in human’s enhanced endurance capabilities.



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