Final answer:
Radioactively labeled DNA probes enable scientists to identify and quantify specific mRNA sequences and to locate where they are expressed in cells. They are used to detect and study specific genes, including differentiating between normal and mutated genes.
Step-by-step explanation:
Radioactively labeled DNA probes are a crucial tool in molecular biology used for studying heredity. They allow scientists to identify and quantitate mRNA, as well as locate transcripts within cells. These probes, which can be tagged with radioactive phosphorus or a fluorescent dye, are designed to be complementary to specific sequences of nucleic acids. This enables them to hybridize, or bind, to the matching DNA or RNA in a sample.
When a sample's DNA is denatured to make it single-stranded, the labeled probe can anneal to specific sequences, revealing the location or quantifying the amount of the gene of interest. Applications of this technique include differentiating between normal and mutated genes, determining the pedigree of a disease, and detecting the presence of extracellular genes.
By enabling the visualization and measurement of specific sequences, these probes are invaluable in genetic research, diagnostics, and many other areas of biological science.