Question

DNA probes are used in human for

• A. Disease diagnosis
• B. Disease control
• C. Disease resistance
• D. Disease tolerance

Answer 1

Answer: (A)

Disease diagnosis

In molecular biology, a DNA probe is a fragment of DNA of variable length (usually 100-1000 bases long), which is used in DNA or RNA samples to detect the presence of nucleotide sequences (the DNA target) that are complementary to the sequence in the probe. The probe thereby hybridizes to single-stranded nucleic acid (DNA or RNA) whose base sequence allows probe-target base pairing due to complementarity between the probe and target. The labeled probe is first denatured (by heating or under alkaline conditions such as exposure to sodium hydroxide) into single stranded DNA (ssDNA) and then hybridized to the target ssDNA (Southern blotting) or RNA (Northern blotting) immobilized on a membrane or in-situ. To detect hybridization of the probe to its target sequence, the probe is tagged (or "labeled") with a molecular marker of either radioactive or (more recently) fluorescent molecules.

DNA probes are used in humans for disease diagnosis not for disease control, disease resistance and disease tolerance. It is based on the fact, these probes go and bind to particular DNA or RNA sequences in human body which are causing disease. So, a particular disease can be diagnosed. Thus, option A is correct.