Analyzing data for chimpanzee skulls
Author: Ashley Laster | Major: Biology | Semester: Spring 2024
My name is Ashley Laster, and I am a Fulbright student studying biology on the pre-dental track. Over the course of the spring 2024 semester, I have been conducting research on the effects of antemortem tooth loss (AMTL) on primates under my mentor, Dr. Claire Terhune. AMTL is the tooth loss that occurs before death in an individual. AMTL is prevalent in humans and many primate species and can affect mandibular movement and diet.
As a pre-dental student, I was very curious about the effects of tooth loss on the skull and mandible shape. I volunteer at a free extraction clinic and would often see firsthand the patients struggles with compromised chewing abilities and jaw discomfort due to tooth loss. This experience sparked a burning curiosity within me to investigate the effects of AMTL on skull and mandible shapes in primates.
I met with Dr. Terhune multiple times to discuss my research topic and plans to research before joining her lab. She helped me come up with different methods and programs to start my research journey. I am extremely thankful to have her as my mentor and for her expertise on the subject.
In my study, I am looking at the effects of AMTL in gorillas, humans, and chimpanzees. I am analyzing skull and mandible shapes by looking at geometric morphometrics through programs like MorphoJ and R, I have found significant results, which are a difference in the mandible shape for humans. I have also found that there is not enough significant data for determining the correlation of mandible shape and ATML in gorillas and chimpanzees, but I am continuing to run more tests. In comparing the species, I have found that humans experience greater AMTL than the other primates in the experiment. In each species I have also compared genders. In humans and chimpanzees, females experience more ATML than males. In gorillas, however, the rates of AMTL are greater in males than in females. When looking at pulp cavity exposure, the findings were the same for genders and species as the AMTL. Also, when comparing posterior (premolars, molars) AMTL versus anterior (incisors, canines) AMTL, humans had more posterior AMTL while gorillas and chimpanzees had more anterior AMTL. One of the main challenges I faced throughout this process was learning the different databases, MorphoJ and R. I had never had much experience with these databases, so it was a challenge to learn the software and coding techniques. Dr. Terhune has been extremely helpful throughout this process. Throughout the semester, we have had weekly meetings where she would evaluate my progress and answer all of my questions about the databases.
Throughout this process, my organizational skills and reading comprehension skills have significantly improved as I am handling multiple amounts of data and reading different scientific articles to learn about the effects of AMTL. Next in my research, I am continuing to analyze the data from the primates and plan to start using Chi-squared and Fisher’s exact tests to compare the rates of AMTL between tooth types, species, and genders. I will also be presenting my findings next March at the AABAs in Baltimore, Maryland.
The Honors College Research Grant has allowed me to pursue my research and gain valuable knowledge about the effects of tooth loss and research techniques. I am extremely grateful for the opportunity to research something extremely important to the dental community.