Screen for Photoreceptor and Other Eyespot Defective Mutants in Chlamydomonas

Abstract

The purpose of this project was to test mutant strains of Chlamydomonas reinhardtii for a variation in eyespot location and size. The technique of phototaxis was used to determine if mutant strains have an altered ability of light reception. Cells from 96-well plates were transferred into the respective tubes filled with 2.2 mL of M medium. One row of tubes was placed in a test tube rack and two racks were placed in each phototaxis box. After twenty minutes in each box, where the only amount of light being let in is from a tiny slit directed on the sample, the tubes were removed and then checked for completion of phototaxis. After noting whether the samples completed phototaxis or not, the phototaxis-negative cells were regrown for further observation and ultimately a PCR screen for the mutant gene sequences. Out of roughly 5,000 mutant samples screened using phototaxis, twelve samples were phototaxis-negative and only four of the twelve samples were phototaxis-negative the second trial. Further experimentation would include the observation of the eyespots under a microscope, culturing these samples, harvesting the DNA via electroporation, and screening the samples using PCR.