PCR, qPCR and qRT-PCR
How to Prevent False Results in Colony PCR
How to Prevent False Results in Colony PCR Colony PCR saves time and reduces costs by eliminating the need for plasmid purification. However, confounding results abound — but only if you fail to anticipate them. This article outlines the major perpetrators of false results and how to prevent them. For a more general overview of…
Read More Multiplex Ligation-dependent Probe Amplification (MLPA)
Multiplex ligation-dependent probe amplification (MLPA) is a molecular technique developed by MRC-Holland back in 2002. In a nutshell, MLPA is a sensitive technique that allows quantification of nucleic acid sequences, quickly and efficiently. It is performed in many laboratories worldwide, and can be applied to detect copy number changes (like deletions or duplications) of a…
Read More Site-Directed Mutagenesis Tips and Tricks
There are a few different ways of approaching site-directed mutagenesis. Here, I’ll give you a quick introduction to inverse PCR and why it’s useful, as well as going through a full protocol for SDM using modified primers!
Read More Immuno-PCR: A Highly Sensitive Method of Immunodetection
Researchers have relied on immunodetection techniques such as Western blotting, flow cytometry and Enzyme-Linked Immunosorbent Assay (ELISA) for years, but immuno-PCR is a relatively new method. By merging an ELISA with the Polymerase Chain Reaction (PCR), immuno-PCR provides extremely high levels of assay sensitivity. ELISA An ELISA is an assay in which a molecule is…
Read More Small Differences that Matter: Detecting Microsatellite Polymorphisms
If you have any training in genetics, chances are that during the course of your education you ran into those funny little sequences called microsatellites. These are repeated tandem motifs 1-6 nucleotides long, scattered all over our genomes. These used to be called “junk DNA,” because researchers thought that the repeats served no purpose. Nowadays,…
Read More Primer Validation Was a No-Go – Now What?
The primers for your gene of interest have finally arrived in the mail, and you’re ready to figure out whether your favorite gene’s expression level is elevated in those precious tissue samples. Only one small last step before you can proceed. Primer validation. This is a standard procedure where you run PCR or qPCR on…
Read More The qRT-rtPCR Control You Should Be Doing, But Probably Aren’t
Every man, woman, and dog is doing quantitative real time reverse transcriptase PCR (qRT-rtPCR) these days. It’s a great method to measure your favorite transcript’s expression levels. One of the big plusses (like the Swiss flag!) of quantitative PCR in general is its high sensitivity. In principle, it can detect and quantify one molecule of…
Read More Quantifying Allele-Specific Gene Expression Using PCR-Based Methods
Allele-specific expression can occur for various biological reasons, such as gene imprinting, or differential transcription caused by mutations, or single nucleotide polymorphisms (SNPs), or epigenetic alterations. Traditional end-point RT-PCR or qRT-PCR-based methods only detect overall levels of mRNA expression from a given gene rather than mRNA transcripts originating from individuals. If your project requires more…
Read MoreDecisions, Decisions: How to Choose the Best qPCR Probe for Your Experiment
Before we go any further, we have to get some things straightened out: RT-PCR versus qPCR versus RT-qPCR. Sooo confusing, amirite?? They all refer to specific molecular biology assays, but the names are unfortunately used interchangeably, which can be awfully confusing for just about anyone. So without further ado: RT-PCR is short for reverse-transcriptase PCR,…
Read More How to Survive a Difficult PCR
I am sure many of you have been there. Everything is going smoothly, and your project seems to be working out perfectly. And then there is this one PCR. For some reason, it just won’t work. It is a black dot on your record. Even though I have a scientific mind, I have to be…
Read More Amplify Your PCR Success with the Right PCR Instrument!
Nowadays, almost every biology lab has a PCR instrument — from portable, battery-operated machines, to “PCR-by-water baths”, do-it-yourself PCR, or familiar vendor packages, including those with real-time quantification or droplet digital capabilities, DNA amplification depends on a robust thermal cycler. If you are looking to upgrade, add to, or even replace the lab’s current PCR…
Read More Microsoft Excel Can Help You Set Up Multi-Well Plates
When you are a newbie to qPCR or qRT-PCR, it is quite common to write everything down in your lab notebook and then tediously mark off reagents or samples as you add them. People typically start with a master mix for items you add to multiple samples such as (Mg2+, dNTPs, 10X PCR buffer, additives,…
Read MoreIntercalating Dyes or Fluorescent Probes For RT-qPCR?
The unique feature of real-time quantitative polymerase chain reaction (RT-qPCR) is that it associates the amplification of your target gene with a fluorescent signal in a quantifiable manner. Presently, there are numerous fluorescent tool kits/methods to consider when designing your RT-qPCR experiment. However, the two major categories to choose from are fluorescent intercalating dyes and…
Read More Oligo Purification Methods: How, Why and for What?
Who amongst us hasn’t had the need for oligonucleotides in an experiment? It is a cornerstone in many procedures and techniques. Depending on the goal, it can be very hard to design just the right oligo for your experiment. Oligos must have the right length; the right amount of C-G, T-A; they can’t form secondary…
Read More The Inhibitors Haunting Your PCR
It often happens that you do everything right with a PCR. You have perfectly isolated template DNA, used sterile tubes and tips, used clean reagents, and said a quick prayer to the PCR Gods. And still, something unknown messes up your results. This unknown at work is generally a PCR inhibitor. Before you blame it…
Read MorePCR Pitfalls: The Devil is in the Details
PCR was actually one of the first lab techniques I learned as an undergrad. Despite being sometimes labeled as a pretty basic lab skill, PCR doesn’t always work as expected. This “fickle” success is due to small details or hidden hazards within the PCR workflow that can cause your seemingly uncomplicated experiment to fail. This…
Read More Divide and Conquer: How to Setup Your First Droplet Digital PCR Experiment
Droplet digital PCR? It’s easy. Because we’re here to guide you through it. We recently introduced you to the principles of digital PCR technology and how it differs from qPCR. In a nutshell, digital PCR is an end-point PCR technology that divides a single PCR into a large number of partitions, and then perform PCR…
Read More How to Choose the Correct Reverse Transcription Method
Quantitative Reverse transcription PCR (RT-qPCR) is frequently used in the lab to detect and quantify RNA expression in a sample. The first step of the assay is to convert the labile RNA to its complementary DNA (cDNA) counterpart through reverse transcription (RT). In fact, RT is the first step in a variety of molecular biology…
Read MoreSmall Particles (Things) Matter!- Introducing Nanoparticle PCR
There are many different methods and protocols on making your PCR run more efficiently. I recently came across an interesting PCR method called “nanoparticle” PCR. This method seems to attract a lot of attention, because it enhances a PCR by a few orders of magnitude. More interestingly, while the enhancement effect has been reported in a…
Read More An Introduction to MassTag PCR
New ways to perform PCR emerge all the time. This speaks for the speed of technological advances, and reflects the ongoing need to keep up with fast-moving research. We all know that PCR’s main purpose is to amplify a stretch of nucleic acids based on sequence-specific primers. Nowadays, a wide range of PCR techniques exist,…
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