I wonder about the minimal size of a DNA FISH probe, taking into account the possibility to amplifiy the signal (like HCR). Most of the literature on DNA FISH probes I found accounts for Kb/Mb sized oligos... but most of them are not using high amplification technology, but rather nick translation + anti-DIG/Fluo/biotin IHC amplification.
I am envisaging a probe around a 100bp for instance.
Cross-hybridization of one probe to several targets occurs more often with cDNA microarrays than with gene-specific oligonucleotide microarrays. In this article, 25–30mer probes are short oligonucleotide probes and 50–80mer probes are long oligonucleotide probes. Long DNA probes refer to probes of 100–150mer in length.
Probe size can range from few kb to megabases (Mb), depending on the application. Probes of 10–20 kb size are ideal to achieve high-precision localization of the resulting FISH signals, whereas larger probes are more suited for applications in which very high detection sensitivity is required.
FISH involves annealing of DNA or RNA probes attached to a fluorescent reporter molecule with specific target sequence of sample DNA, which can be followed under fluorescence microscopy.
The FISH test produces results in a few days, unlike cytogenetic testing, another procedure that looks for chromosomal abnormalities but may take weeks. FISH testing may find many of the same abnormalities as cytogenetic testing and detect others too small to be picked up by cytogenetic testing.
There are three basic types of probe used in emergency and critical care point-of-care ultrasound: linear, curvilinear, and phased array. Linear (also sometimes called vascular) probes are generally high frequency, better for imaging superficial structures and vessels, and are also often called a vascular probe.
Fish species are commonly used as experimental models in the laboratory. DNA is routinely collected from these animals to permit identification of their genotype. The current standard procedure to sample DNA is fin clipping, which involves anaesthetising individuals and removing a portion of the caudal fin.
They reduce signal amplitude by a factor of ten. Usually by incorporating a 9 megaohm resistor in the probe tip to act as a voltage divider. This added attenuation makes 10x probes good for high-voltage measurements.
Dear Alexis Assens
You can use 100bp fluorescent probe for amplicons (the product following PCR amplification).
This technique is used commercially to diagnose specific point mutations/variants in a particular segment of DNA/gene.
Shorter probes can have non-specific hybridization to other non-target regions when used on genomic DNA, creating wrong interpretations.
DNA FISH (fluorescence in situ hybridization) probes are typically composed of small oligonucleotides that are specifically designed to target and bind to specific sequences in the genome. The size of a DNA FISH probe can vary widely, depending on the specific goals of the experiment and the nature of the target sequence.
In general, smaller DNA FISH probes tend to be more specific and less prone to non-specific binding, but they may also have lower signal intensity and may be more difficult to detect. In some cases, it may be possible to amplify the signal from small DNA FISH probes using techniques such as HCR (hybridization chain reaction), which involves using enzymes to amplify the probe signal through a series of enzymatic reactions.
In terms of the minimal size of a DNA FISH probe, it is generally possible to use probes as small as 15-20 base pairs in length, although the sensitivity and specificity of such small probes may be limited. Probes in the range of 50-100 base pairs in length are often used in DNA FISH experiments, and may be amplified using techniques such as HCR to improve the signal intensity.
It is important to note that the optimal size of a DNA FISH probe will depend on the specific goals of the experiment and the characteristics of the target sequence. In some cases, it may be necessary to use larger probes to ensure sufficient specificity and sensitivity, while in other cases smaller probes may be sufficient.
- Badges
- Science topic
- Similar topics
- Biological Science
- Microbiology
- Virology
- Virus