Difference Between VNTR and Probe

The key difference between VNTR and probe is that VNTR is a short nucleotide sequence occurring as a tandem repeat in the genome while a probe is an artificially synthesized short sequence of DNA or RNA that could be radioactively labeled.

VNTR stands for variable number tandem repeat. It is a short nucleotide sequence organized in tandem repeats in the genome. VNTRs are naturally occurring in our genome. A probe is an artificially synthesized short DNA or RNA sequence. Both probe and VNTR are nucleic acids or short nucleotide sequences. They have immense use in different molecular biological techniques, mainly in forensic studies. VNTR and probe share some similarities as well as differences. Hence, the article attempts to highlight the difference between VNTR and probe.

CONTENTS

1. Overview and Key Difference
2. What is a VNTR
3. What is a Probe
4. Similarities Between VNTR and Probe
5. Side by Side Comparison – VNTR vs Probe in Tabular Form
6. Summary

What is a VNTR?

VNTR is a short nucleotide sequence that exists as a tandem repeat in our genome. VNTRs are present in many chromosomes. Furthermore, VNTRs differ among different individuals from the lengths since the number of repeats is different in VNTRs of different people. Basically, it is due to alleles inherited from their parents. Therefore, we mainly use VNTRs for parental identifications (inheritance) or for personal purposes. Similarly, it is also possible to use them in genetics, forensics, biological research and DNA fingerprinting. Therefore, VNTR is an important tool in molecular biology.

In inheritance, we analyze VNTR data using two basic principles: inheritance matching and identity matching. During inheritance matching, the individual must have a matching allele to that of each parent. During identity matching, both VNTR alleles must be present in a specific location of the genome.

What is a Probe?

In the context of molecular biology, a probe is an artificially synthesized DNA or RNA fragment with a length of 100 to 1000 bases. We can radioactively label these probes. Hence, we use them in detecting target nucleotide sequences that are complementary to the sequence of the probe. When we add probes to the sample, hybridization takes place with the complementary sequences or target sequences and make it easy for us to identify the target sequences. Since probes carry radioactivity, we can detect them easily.

In forensic science, we commonly use probes in DNA profiling techniques such as the detection of short tandem repeat regions, restriction fragment length polymorphisms, and DNA fingerprinting.

What are the Similarities Between VNTR and Probe?

• Nucleic acids are the building blocks of VNTR and Probe.
• We use them in gene identification processes.
• Also, both their lengths are variable.
• They are important tools in forensic studies, DNA fingerprinting, genetics, etc.

What is the Difference Between VNTR and Probe?

VNTR is a region of the genome organized as tandem repeats while a probe is a short DNA or RNA sequence synthesized artificially in order to detect target sequences in a sample. So, this is the key difference between VNTR and probe. Also, an important difference between VNTR and probe is that unlike VNTRs, we can radioactively label the probes.

Moreover, VNTRs mostly perform parental identifications while probes help to detect target nucleotide sequences in DNA or RNA samples that are complementary to the sequence of the probe. Hence, this is also a significant difference between VNTR and probe.

The following infographic presents more information on the difference between VNTR and probe.

Summary – VNTR vs Probe

The common use of VNTR and probe is in molecular analyzing techniques such as forensic studies and DNA fingerprinting. Both consist of variable lengths. However, the key difference between VNTR and probe is that a VNTR is a region of the genome arranged with tandem repeats while a probe is a fragment of DNA or RNA that could be radioactively labeled. Moreover, VNTRs are present in the genome. But, probes are artificially synthesized and could be labeled radioactively to detect target nucleotide sequences in DNA or RNA samples that are complementary to the sequence in the probe. Thus, this is the summary of the difference between VNTR and probe.

Reference:

1. “Variable Number of Tandem Repeats (VNTR) and Its Application in Bacterial Epidemiology.”Science Alert: Journal, Available here.
2. “DNA Probe.” Nature News, Nature Publishing Group, Available here.

Image Courtesy:

1. “D1S80Demo” By PaleWhaleGail at English Wikipedia (CC BY-SA 3.0) via Commons Wikimedia
2. “Molecular Beacons” (CC BY-SA 3.0) via Commons Wikimedia