THREE-DIMENSIONAL STAGING SERIES OF ANOLIS SAGREI

Abstract:

With the rapid rise of Evo-devo and the concurrent development of new imaging techniques, comparative studies of development have accelerated over the last decade. Squamates, lizards and snakes, lack a traditional experimental model species for developmental investigations, yet are important for understanding fundamental evolutionary questions because of their remarkable diversity. However, several squamate species have growing communities of biologists building new resources for comparative and experimental studies of lizard development. Creation of detailed embryological atlases for these species will help promote their advancement. In the past, scientists have had to rely on destructive methods to take apart biological samples which allows them to visualize the three-dimensional (3D) anatomy. However, X-ray computed tomography, CT scanning, allows for sub-10 micron, non-destructive imaging of vertebrate embryos. This technique allows not only the ability to analyze the hard tissues, but also, with the help of chemical counterstains, the ability to differentiate among soft tissues. I created a detailed, 3D embryological atlas of the model lizard species, Anolis sagrei, using micro-CT scanning. For a subset of stages I reconstructed the development of both hard and soft tissues, such as bone, muscle, and neural tissues. All reconstructions were performed in the free software package 3D Slicer. This anatomical atlas will be essential for future research on Anolis development, will build a comprehensive understanding of the embryonic development of anoles, and may provide a reference for people investigating the development of other lizards.

 

Acknowledgements:

I would like to thank all the people who made this dissertation possible, starting with my amazing advisor Dr. Thomas Sanger, for his support, insight, advice, and mentoring throughout the development and completion of my research project. He was the invisible hand that nudged me on the right path, particularly when it came to the direction of this project and the voice of reason that got me out of many moments of impostor syndrome and self-doubt. I thank the members of my thesis committee, Dr. Martin Berg and Dr. Joseph Milanovich, for their advice and guidance. Your encouraging words and thoughtful feedback have been very important to me. I would also like to thank the graduate program director Dr. Terry Grande for always looking out for me and the other biology graduate students and always having our best interests in mind. I want to thank Joseph Schluep, for regularly providing µCT scanning assistance and for fixing the µCT scanner bed for me during a time when a replacement would’ve taken weeks to ship in.

Special thanks goes to all the Sanger lab people who aided in collections and processing.

 

Hannah Maher, Jillian Schuberth, Alexandrea Turnquist, Gannon Cottone, Arlisse Lim, and Michelle Hajduk for egg collection. Alexandrea Turnquist helped with segmentation and three-dimensional model preparation. Go Team AnolisEvoDevo.

Many people have contributed to my wonderful experience at Loyola, including the Biology Department Faculty, the General Biology teaching faculty, and the departmental graduate students. I would like to thank the Department of Biology staff, especially Audrey Berry and Virginia Lorenzo, for making the paperwork more bearable. Thanks to Dr. Megan Helfgott and Dr. Lisa Godsel for giving me the opportunity to teach general biology lab and mentoring me through the process. Biology graduate students, especially Erica Becker, Katherine Starr, Mike Vosburg, and Manny Widuch, thanks for supporting me through these past few years, even if you didn’t quite get my project. The comradery and group support pulled me through tough times.

To my friends and family that provided me with the motivation, encouragement and distractions required for completing this thesis project, I thank you. Finally, I want to thank my mother, Angelika Epperlein, for listening to me constantly rant and talk things out, for reminding me of my goals, and for the sacrifices you’ve had to make for me to pursue a master's degree.

 

Vita:

Lilian Epperlein was born in Tarzana, California, and was raised in Cologne, Germany, and moved to the United States in 2006. She attended the University of Arizona, Tempe where she earned a Bachelor of Science in Biology: Genetics and Cells in 2018.

From 2018 she began her Master of Science in Biology at Loyola University Chicago, focusing on the development of Anolis sagrei lizard using CT scanning. This thesis was presented in part at the Society for Integrative and Comparative Biology (SICB 2020). While at Loyola, she also became a co-author on a few papers (Griffing et al., 2021; Sanger et al., 2021),  and enjoyed teaching General Biology Laboratory (BIOL 111 and 112).

Currently, Ms. Epperlein is an instructor at Loyola University Chicago.

 

Research Mentor:

Dr. Thomas Sanger

Committee Members:

Dr. Joseph Milanovich

Dr. Martin Berg