Molecular probes are used for many genetic disorder like

Options

A. Duchenne muscular dystrophy
B. cystic-fibrosis
C. Tay-Sachs disease
D. all of these

Answer

### Step-by-Step Solution:

1. **Understanding Molecular Probes**: Molecular probes, also known as DNA probes, are short strands of DNA or RNA that are used to detect the presence of complementary sequences in a sample. They are essential tools in molecular diagnostics and genetic research.

2. **Preparation of Molecular Probes**: These probes are often prepared using a method called the random primer method. This involves denaturing double-stranded DNA that contains the target sequence, followed by the addition of oligonucleotide samples that include all possible sequences of six nucleotides.

3. **Function of Molecular Probes**: Once the probes are prepared, they can hybridize (bind) to complementary DNA sequences in cloned cells. This hybridization allows researchers to identify specific genetic sequences, including those associated with genetic disorders.

4. **Detection of Genetic Disorders**: In the context of genetic disorders, molecular probes are used to identify mutations or variations in genes. For example, when a probe is used to detect a mutated gene, the absence of hybridization (binding) indicates that the gene is mutated, as the probe will not find a complementary sequence to bind to.

5. **Examples of Genetic Disorders**: The question lists several genetic disorders: Duchenne muscular dystrophy, Cystic Fibrosis, and Stesha's disease. All of these disorders are genetic in nature and can be diagnosed using molecular probes.

6. **Conclusion**: Since molecular probes can be used for all the mentioned genetic disorders, the correct answer is that they are used for "all of these" disorders.

### Final Answer:
Molecular probes are used for many genetic disorders, including Duchenne muscular dystrophy, Cystic Fibrosis, and Stesha's disease. Therefore, the correct answer is "all of these."

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