Final answer:
The pGLO plasmid carries the Green Fluorescent Protein (GFP) gene as a marker gene, which fluoresces green under UV light, allowing researchers to identify cells that have taken up the plasmid.
Step-by-step explanation:
The marker gene carried by the pGLO plasmid is the gene encoding for the Green Fluorescent Protein (GFP). This protein, which was originally found in the jellyfish Aequorea victoria, fluoresces green under ultraviolet light. The GFP gene serves as a reporter gene, which allows researchers to visually track whether the plasmid has been successfully taken up by a cell. When cells have incorporated the pGLO plasmid, they can be induced to express GFP, and thus they can be easily identified by their green fluorescence under UV light.
The presence of the GFP gene offers a way to directly monitor the presence of the plasmid without relying solely on antibiotic resistance markers. This is especially useful in molecular biology practices where the monitoring of gene expression and plasmid acquisition by host cells is essential. Moreover, the pGLO plasmid often also includes an antibiotic resistance gene, such as for ampicillin, which provides an additional means of selecting for cells that contain the plasmid.