Labeled, known, short stretches of DNA used to detect a specific sequence of nucleotides in a mixture are known as what?

Labeled, known, short stretches of DNA used to detect a specific sequence of nucleotides in a mixture are referred to as gene probes. These probes can specifically hybridize to complementary sequences of DNA, allowing researchers to identify the presence of particular DNA sequences within a sample. This process is essential in various applications, including genetic testing, diagnosis of diseases, and forensic analysis.

Gene probes are often used in techniques such as Southern blotting, fluorescence in situ hybridization (FISH), and microarray analysis, where the ability to detect and visualize specific sequences is crucial. The labeling of these probes, often with fluorescent or radioactive tags, facilitates the visualization and identification of the target sequences amidst a complex mixture of nucleic acids.

The other options provided don't fulfill the role of detecting specific nucleotide sequences in the same manner. Antisense RNA is a molecule that binds to complementary mRNA, affecting gene expression. DNA polymerases are enzymes involved in synthesizing DNA during replication. Restriction enzymes are proteins that cut DNA at specific sequences but do not serve as probes for detecting sequences. Understanding the function of gene probes is fundamental in molecular biology and diagnostics.