Analysis of the spermtail axoneme following a substitution of Drosophila melanogaster beta 2-tubulin with Anopheles gambiae beta 2-tubulin: functional or not?
Christian R Jensen
How does a protein evolve while maintaining function? Nature is constantly flowing like a raging river; the consistent flow does not readily allow for a pause to chart a course through the dangerous waters. Much like navigating violent waters, nature must take a specific narrow path when making changes in the genetic code; one misstep can result in a loss of function. Our model focuses on the beta 2-tubulin found in Drosophila melanogaster; past research has demonstrated that beta 2-tubulin has a major role in the formation of a functional 9+2 spermtail axoneme. Through phylogenetic analysis it has been determined that the D. melanogaster beta 2-tubulin sequence has not been altered for at least 110 million years; this is highly unusual in the scope of nature. Although there have been no recent changes in the Melanogaster sequence, there are marked changes in the beta 2-tublin sequences among Melanogaster’s close relatives. Anopheles gambiae and Melanogaster shared a common ancestor around 220 million years ago, however there are 40 amino acid differences between the two beta 2-tubulin sequences. This proposal aims to create a transgenic organism; the Melanogaster beta-2 will be replaced with the Anopheles beta-2. If the resulting spermtail is functional, it will show that the 40 changes in the Anopheles sequence followed a specific, precise path that allows it to remain functional within the Melanogaster domain. However, it is possible that the substitution will result in the spermtail axoneme being compromised and a loss of spermtail function. This would show that there has been a significant evolutionary event since the divergence 220 million years ago; this event effectively prevents further adaptive changes from occurring in the Melanogaster beta-2 sequence.
Honors Thesis - Undergraduate
Mark G. Nielsen
Primary Advisor's Department
Stander Symposium project
"Analysis of the spermtail axoneme following a substitution of Drosophila melanogaster beta 2-tubulin with Anopheles gambiae beta 2-tubulin: functional or not?" (2017). Stander Symposium Projects. 1109.