Question

When a gene or cDNA probe is "labeled", what is the process of labeling actually mean exactly?

For example, if c-myc is labeled with a 32p dCTP, what does this mean exactly?

Answer 1

When a fluorescent tag is chemically or biologically attached to a specific functional group or region on the target molecule then that is known as labeling. Labeling is done to aid in the process of identification of hybridization process or detection of a biomolecule/particular target.

In simple terms labeling can be thought as attaching a fluorophore or fluorescent tag to a gene so that the target selected can be detected after a particular activity. Labeling of a probe is based on the type and nature of the probe and tag. c-myc is labeled with 32p dCTP means that 32p dCTP is attached to c-myc so that detection of c-myc in certain conditions is made possible. Since 32p dCTP is a "tag" therefore it is "labeled" on c-myc.

(Note- In layman terms you can understand labeling as attaching, but with a fluorescent tag)