Alec Jeffreys developed the DNA fingerprinting technique. The probe he used was

Options

A. SNP
B. sex chromosomes
C. rDNA
D. VNTR

Answer

**Step-by-Step Solution:**

1. **Understanding DNA Fingerprinting**: Alec Jeffreys developed the DNA fingerprinting technique, which is a method used to identify individuals based on their unique DNA patterns.

2. **Identifying the Probe Used**: The question asks about the specific probe used by Alec Jeffreys in his DNA fingerprinting technique. The options provided are SNP (Single Nucleotide Polymorphism), sex chromosome, rDNA (ribosomal DNA), and VNTR (Variable Number of Tandem Repeats).

3. **Evaluating the Options**:
- **SNP**: This refers to variations at a single nucleotide position in the DNA sequence. While SNPs are important in genetics, they are not the basis of DNA fingerprinting.
- **Sex Chromosome**: These chromosomes determine the sex of an individual (X and Y chromosomes) and are not directly related to DNA fingerprinting.
- **rDNA**: Ribosomal DNA is involved in the production of ribosomes and does not play a role in DNA fingerprinting.
- **VNTR**: This stands for Variable Number of Tandem Repeats, which are repetitive sequences in the DNA that vary in length among individuals. Jeffreys discovered that these VNTRs can be used to distinguish one individual from another.

4. **Conclusion**: The correct answer is VNTR (Variable Number of Tandem Repeats). Alec Jeffreys used VNTRs as the probe in his DNA fingerprinting technique to identify individuals based on the unique patterns of these repeats in their DNA.

**Final Answer**: The probe used by Alec Jeffreys in DNA fingerprinting was VNTR (Variable Number of Tandem Repeats).

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