Jacob Presch
Master's Thesis Defense
Advisors: Dr. Carlos Infante, Dr. Annika Mosier and Dr. Gregory Ragland
Date: July 24, 2026
Time: 2:00pm – 3:00pm
Location: North Classroom 1403
Genetic Factors Affecting Forelimb Versus Hindlimb Identity in Eublepharis Macularius
The genome is expressed through the interactions between genes and their regulatory elements, inducing differential expression across space and time. In developing embryos, the interplay between genes and their regulators, and the modulation of cis-acting regulatory elements, remains the best description of how tissue-specific morphology can be produced without the disruption of embryonic development. The vertebrate limb has long functioned as a model to study molecular signaling; the changes to the molecular signaling in the limb have been linked to the wide diversity of limbs seen across vertebrates. Within squamata, Gekkota represents the oldest limbed clade as the sister group to all snakes and lizards, which diverged ~250 million years ago. The inclusion of gecko limb offers an inclusive lens to investigate the basal development of the morphological limb-diversity and limb loss seen across Squamata. In this thesis, I examined the developing gene expression and regulatory profiles of the limbs of Eublepharis macularius and compared these to similar data from Anolis lizards, a clade of lizards that have undergone extensive morphological diversification of the limbs in response to differing needs of locomotion. The differences between these species' limb morphology are thought to arise from differential expression of limb genes enabled by differences in regulatory control during development. Through RNA-seq and ChIP-seq, I characterized both the differential expression and regulatory elements within the forelimbs and hindlimbs of Eublepharis macularius and compared them to Anolis lizards to generate a basal expression profile of squamate limb development. The ChIP-seq experiment was not able to produce discernible results; however, the RNA-seq experiment identified a known core limb gene network across squamates and identified many differentially expressed genes in both species. Across both datasets, the identification of these many differentially expressed genes supports that relatively small changes in the expression of many developmental genes may describe the drastic morphological variations seen across vertebrate limbs.