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PCR, qPCR and qRT-PCR

Control your error! How to minimize pipetting error and get low SDs in qRT-PCR

Variability is the Achilles’ heel of research. It can often confound our results and lead us astray searching for solutions. There are two kinds of variability, the first is biological variability. This represents the stochastic nature of the sample you are working with and the inherent differences between samples from the same conditions. There is…

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When PCR Gets RACE-y: From Unknown mRNA Segments to Sequenced cDNA

Normally you need two primers to amplify your segment of interest – one for the 3′ end of your segment of interest and one for your 5′ end. But if you don’t know the sequence of the regions you’re hoping to amplify this can be a problem! Rapid Amplification of cDNA Ends (RACE) is a…

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How to Quantify Integrated HIV Genomes Using Alu-gag PCR

Alu sequences are repetitive DNA sequences that are widely dispersed within the human genome. These “junk DNAs” are not as useless as one might think. An interesting method to use them is to quantify the number of integrated Human Immunodeficiency Virus (HIV) genome copies using Alu-PCR.

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Touchdown PCR: A Primer and Some Tips

When I first heard of touchdown PCR, I thought of a landing aircraft, which, as it turns out is not a bad way to think about it. But despite it’s amenability to analogies and dreadful puns (see title), touch-down PCR (TD-PCR), a very useful technique for improving PCR amplification specificity, is trickier that it might…

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Do You Know Where You Are? Find Out with Genome Walking

Do you work with plants? Are they genetically engineered? Do you know where and how? If not, you could experience problems. After all you do not want your transgenic gene cassette to disrupt genes that would affect your phenotype of interest. In this article I will tell you about Agrobacterium-mediated transformation – a widely used…

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2015 Staff Picks: PCR & Real-time PCR

To wrap up 2015, we’re highlighting our favorite articles from the year. These articles were handpicked by our editorial staff here at Bitesize Bio. So, sit back with your cup of coffee (or beverage of choice) and enjoy these fantastic articles from 2015. First up, we have the category of PCR & Real-time PCR. Jen…

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How Thermophilic Bacteria Survive, Part II: DNA

In part I, I answered the question, “How do proteins in thermophiles survive under high temperatures?” In this part, I’ll look look at how nucleic acids survive -thrive, even- in conditions that are too hot for most of us, but ideal for a number of organisms, including the one that gave us Taq polymerase and…

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Long-Range PCR: It’s About Choosing the Right Enzyme

The ability for DNA polymerase to copy a long stretch of DNA is becoming increasingly important. Why? It has to do with the advances in our sequencing technologies. Our next generation sequencing (NGS) technology requires the DNA polymerase to copy a long stretch of DNA (sometimes up to 50kb) as NGS is churning out genetic…

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Photonic PCR: When Lightening Strikes Your DNA

Before I get into today’s topic, please allow me to digress a bit and start with a few sentences that sum up the polymerase chain reaction (PCR); the grand-daddy of molecular biology. PCR, a method that is at the heart of modern day molecular biology discoveries, is a process that amplifies genetic material through our…

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PCR Problems? Try an Additive

You’ve tried all the usual stuff, and checked the primer sequences twice, but still can’t get that PCR fragment amplified. It’s time to enter the strange world of PCR additives. Over the years a variety of additives have been shown to enhance PCR reactions in certain situations. Here is a summary of some of the…

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Time to Instigate Nested PCR

How to Obtain a Purer PCR Product and Reduce Non-specific Amplification Unless you’ve gotten your hands on some miraculously specific primers, amplification of only your target sequence without non-specific amplification can be very challenging. Thankfully, a clever and surprisingly simple solution is at hand! A Quick Recap of the Basics In PCR, you design your…

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Get that Genotyping PCR to Work EVERY TIME

Say you just joined a lab and have been assigned your very own project to work on. As part of your new responsibilities, you have to breed and maintain the mutant (or transgenic) mouse line which you will be using for your experiments. An integral part of mouse genetics experiments is determining the genotype of…

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Are You Ready for Your First qPCR?

Hope you had a heavy breakfast, because the first qPCR is going to take time. Did you remember to fill your coffee cup? There are a lot of intricacies in qPCR that will need your neural networks to be brisk. How qPCR differs from traditional PCR Unlike traditional PCR, qPCR measures the amplification of DNA…

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10 Tips for Consistent qPCR

Quantitative PCR (qPCR) uses fluorescent dyes or probes to visualize the amplification of specific DNA sequences as it happens (i.e. in real time). The dyes or probes fluoresce when they bind to newly amplified DNA, and the amount of fluorescence emitted is proportional to the amount of DNA (or mRNA) present in the original sample. By detecting newly synthesized DNA…

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Life of the Party: Viability PCR (vPCR)

Viability PCR (vPCR) is a big step forward in PCR technology. Through the use of a simple pre-treatment of the sample(s) of interest using specific intercalating reagents, it is possible to neutralize the DNA of dead cells. As a result, only DNA from live cells will be amplified by PCR. Through the vPCR, it’s possible to…

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qPCR Tips: Workflow, Applications and Troubleshooting

In this webinar, you’ll get: Practical advice for sample preparation, qPCR setup and result analyses Guidance on choosing the correct fluorescent labeling system for your qPCR Tips to troubleshoot the most commonly encountered issues in qPCR Join Dr. Karen O’Hanlon Cohrt for a practical tour of the process, applications and practice of qPCR, from start…

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Designing Luck: 8 Basic Concepts for Designing Primers for a Standard PCR

I think we all have been through those my-PCR-product-didn’t-get-amplified days. Sometimes, playing around a bit more with the PCR-conditions brings luck, or sometimes it doesn’t work at all. These days we have access to many different types of DNA polymerases, ultrapure and buffered nucleoside triphosphates, and other necessary starting materials in convenient concentrations; but still…

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Get To Know Your DNA Polymerases

While most may think standard Taq is the backbone of PCR, there are many other DNA polymerase options out there. The polymerase you use has a significant impact on the efficacy of your PCR, specifically on the product yield, the purity of the product and the faithfulness with which the starting product is transcribed. Sometimes,…

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To boil? Or be boiled? Saving Time With Colony PCR

Applying molecular techniques to unicellar organisms leads to many questions… Did my electroporation work? Is my vector inside my competent cell? Do I have contamination in my liquid culture? Is this the correct bacterial strain the neighboring lab promised me it is? Did the guy from the other side of the world send me the…

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Detecting Signal in qPCR: From DNA Binding Dyes to BHQ Probes

A Brief History of Detecting Amplicons The Old Days of Ethidium Bromide In the early 1990s, quantitative (q) PCR was in its infancy, and despite PCR itself already being around for 10 years, there were no easy ways of precisely quantifying the amount of DNA that was amplified in a PCR reaction. In those days PCR…

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10 Handy Tips to Help Keep Your PCRs Contamination Free

PCR contamination can be your worst nightmare if you are not able to figure out the source of the bands in your negative control. Initially, when I had to setup PCRs, contamination was my main problem and it remained a mystery for a while, as no matter how many times I repeated it with a…

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Keeping On Top of Housekeeping Genes

Want to measure how much mRNA you have in a particular sample? Easy! Make some cDNA, add some fluorescent DNA-intercalating dye, pop it into a quantitative real-time PCR (qRT-PCR) machine and Bob’s your uncle! You have your result! Easy right…? Not so fast. As with any scientific assay, qRT-PCR requires some optimization. First, you need…

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How to Be Greener – The Environmentally Friendly Guide to PCR

Science is an expensive business and those who use high energy-demanding techniques may not even realize just how expensive they are. The Cost of PCR Let’s looks at PCR. You need to pay for the machine, all the ingredients including expensive enzymes, a freezer and a fridge for your ingredients, tubes and caps, not to…

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Modify Your Oligos, Modify Your Experiments

If you’ve ever performed PCR, you’re probably already very familiar with DNA oligonucleotides (or oligos). But did you know that these molecules can do so much more than just act as simple primers? You can add a wide range of modifications to your oligos, which may change the stability, binding, solubility and even visibility, to…

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Loop-mediated Isothermal Amplification

Loop-mediated Isothermal amplification (LAMP), is an emerging technology that allows DNA amplification at a constant temperature. The key to this principle is the use of a DNA polymerase that possesses strand displacement activity. As a result of this property there is no need for heat denaturation of double stranded DNA in order to allow primer…

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Finding Nemo: Understanding Single Cell Isolation and PCR Amplification

Every protocol for single cell PCR can be broken down into two steps. In the first step, the cells are isolated by micromanipulation, laser capture microdissection, flow cytometry, or by direct micropipetting. Next, the genetic material is processed by PCR to amplify your sequence of interest. Here, we’ll go through the different options for isolating…

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qPCR: RNA Quality and Why It Matters

Gene expression analysis plays a pivotal role in a wide range of studies, including biomedical analysis and diagnostics. Of all the methods available for gene expression analysis, quantitative real-time PCR (qRT-PCR) is the most rapid, sensitive, and accurate to measure mRNA, and its use in clinical diagnostics is rising steadily. RNA quality entails both purity and…

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Overhang PCR

Have you ever “accidently” forgotten to add the Kozack consensus sequence to the start of a coding genes? Or forgotten to include the stop codon? Did you clone something, then realize you wanted to tag it with something? Or you just want to add restriction enzymes to your PCR product to make it easier to…

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An Essential Toolbox for qPCR Users

Today, PCR is as common a feature to the lab as pipettes and beakers. The majority of us regularly need to amplify our DNA or RNA samples, sometimes for an ‘everyday’ PCR run just to check if our primers actually work, or in a quantitative (q)PCR run, where we might be comparing the levels of…

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Mediator Probe PCR

Want a PCR method that gives you high sensitivity and is cost-effective? Then you might want to try Mediator Probe PCR.  This method gives you sensitivity and limit of detection comparable to that of dual-labeled hydrolysis probes without the high cost. We all know how expensive small batch probe synthesis orders can be, especially when…

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Understand and troubleshoot PCR with The BitesizeBio Guide to PCR

Over the years, I’ve had my fair share of ups and downs in the lab. The latter quite often centering on a failed or plainly weird PCR experiment. As I’ve gone on and become ever more fastidious about my lab practices I’ve realized that the majority of these little calamities were perfectly avoidable. In my…

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Thermal Asymmetric Interlaced PCR (TAIL-PCR)

What do bunnies, coins and PCR have in common? They all have tails! (ha ha!) Thermal asymmetric interlaced PCR or TAIL-PCR is used to sequence and analyse unknown DNA fragments that are adjacent to known sequences. Think of it as being rather like networking. You know you want to get to know someone so you…

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Polymerase chain reaction-enzyme-linked immunosorbent assay (PCR-ELISA)

As researchers, we are constantly on the lookout for new and improved ways to analyze, detect and quantify our favorite protein or gene. Luckily, we don’t always need to reinvent the wheel! PCR-ELISA is a good example of where two commonly used techniques have been merged together to create a very powerful analytical tool. What…

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