Date of Award


Publication Type

Master Thesis

Degree Name



Great Lakes Institute for Environmental Research

First Advisor

Cristescu, Melania (Great Lakes Institute for Environmental Research)





Creative Commons License

Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License
This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 4.0 License.


Understanding the genetic basis of adaptation is a central task for evolutionary biology. Here, I examined how Ldh gene expression contributes to the adaptation of Daphnia pulex and Daphnia pulicaria by using a controlled acclimation experiment. There were no statistically significant changes (p>0.1) in gene expression due to changes in temperature, dissolved oxygen. However, both LdhA and LdhB expression were significantly different in each type of Daphnia (pond, lake or hybrid) suggesting that these genes could contribute to adaptation or could be linked to loci that do. LdhA was expressed significantly more than LdhB (p<0.005), in all clones. Analysis of the protein structures of LDHA and LDHB revealed that both are functional LDH proteins, with very similar secondary structures. These results confirm that while the protein structures of LdhA and LdhB where very similar, expression of these genes could contribute to the adaptation of pond and lake Daphnia.