The Effects of Different Fluorescent Proteins On E.coli Fitness and Overall Cell Growth

Different populations within an environment must compete for nutrients and space. The survivor is considered more fit, and the phenomenon as a whole is known as survival of the fittest. It is usually assumed the more fit organism produces less offspring and will be the only organism that survives. However, the “less-fit” organisms are not always destined to die, and our understanding of biological fitness and survival is not as simple as we believe. 

To learn more about the phenomenon, a fluorescent protein (FP) was over expressed in a single strain of E.coli and competed in a pairwise manner against the primary colors displayed on a fluorescent protein tree (blue, yellow, green, and red). Fitness was quantified by comparing the growth curve at the initial and final points of the assay. The red and blue FPs were the most fit FPs compared to green FPs being the least fit. However, the less fit FP still displayed substantial growth in the competitions, and did not die off as expected. A further analysis is needed to be done with every FP on the tree to deepen our knowledge of biological fitness.