Functional tests of [beta] tubulins in Drosophila sperm tail morphology

Date of Award


Degree Name

M.S. in Biology


Department of Biology


Advisor: Mark Nielsen


Drosophilid Beta 2 tubulin has not evolved in 60 million years; variant forms of the protein cannot support spermtail function. Here we test if a unique synergism among amino acids 29, 55, and 57 underlies Beta 2's function and stasis, by transforming flies with a chimeric gene consisting of Beta 1 tubulin with Beta 2 codons exchanged at these sites. Sperm of transformed flies undergo tests for fertility, motility and cross-sectional ultrastructure to determine if the chimeric gene supports Beta 2 function. Though transformed flies were not recovered, a second project in related Dipterans suggests synergism may underlie Beta 2's evolutionary stasis. Mosquito Beta 2, and the major Beta 1 and Alpha 1 tubulins, are evolving rapidly in Anopheles mosquitoes. Anopheles mosquitoes have a 9 + 1, rather than 9 + 2 axoneme, possibly relaxing requirements for tubulin function. Alternatively, absence of the Beta 2 synergism may release tubulin evolution.


DNA-binding proteins, Tubulins, Drosophila

Rights Statement

Copyright © 2008, author