Sigma-Aldrich® Advanced Genomics
Maxam-Gilbert Sequencing: What Was It, and Why It Isn’t Anymore
In the mid-1970s, two methods were developed for directly sequencing DNA: the Maxam-Gilbert sequencing (or chemical sequencing) method and the Sanger chain-termination method. Indeed, in 1980, both Walter Gilbert and Frederick Sanger were awarded The Nobel Prize in Chemistry for “their contributions concerning the determination of base sequences in nucleic acids”. Actually, each got a…
Read More An Introduction to Nanopore Sequencing
DNA sequencing is the most powerful method to reveal genetic variations at the molecular level, leading to a better understanding of our body in physiological settings, and pathological conditions. It is the beginning of the long road towards better diagnostics and personalized medicine. Even though there have been great advances in DNA sequencing technologies there…
Read More A Crash Course in CRISPR-Cas9 Editing in Drosophila
How to Test the Efficiency of your sgRNA
To successfully edit your genome of interest, one critical step is to test the sgRNA you have designed. Fortunately there are programs that have been developed such as CRISPRscan for zebrafish, SSC, Sequence Scan for CRISPR, or WU-CRISPR that you can use to predict the efficiency and the suitability of the sgRNA. However, the prediction…
Read MoreMeeting the BioPython
The Biopython Project is an amazing initiative that helps scientists use Python for bioinformatics – and it’s exceptionally easy to learn! You can access online services, parse (read) different file types, analyze, and do a bunch of fun stuff with your data with Biopython. The people behind the project have put in a lot of…
Read MoreProbability Theory and Molecular Barcodes
In biology, a molecular barcode is a characteristic DNA sequence used to distinguish and gather together similar items. Such a simple but powerful concept is useful in various applications. As an example, the Barcoding of Life project aims to identify specimens through the sequencing of standard gene regions, and use these as barcodes. On the other…
Read MoreDemystifying NGS: Depth Coverage and Deep Sequencing
NGS is not a three-headed monster. However, it can be a difficult concept to grasp—especially when you are getting started. There is a lot of new terminology, and a whole new world to discover: both in the lab bench and in interpreting your results. It helps to start somewhere. So, let’s start! Depth of Coverage…
Read More A Primer on Checking the Methylation State of the Genome
We all know that genes encode proteins that make up a living cell. However, the level and coordination of gene expression is really the key to the success of a living cell. One way eukaryotic cells (that’s us!) control protein expression is through addition of a methyl or hydroxymethyl group on the cytosine nucleotide. This…
Read More Show Disparity in Gene Expression with a Heat Map
Have RNA-seq or microarray data? What possible tools can help you find your genes of interest? Is there any pattern in your expression data? I know you are totally at sea but heat maps are now commonly used to help. A heat map is a well-received approach to illustrate gene expression data. It is an…
Read More Phylogenetic Tree Construction Made Easy with Blast & Mega
Your DNA sequence can be put to good use fairly easily with Blast and Mega software. These programs can help in phylogenetic tree construction. You can ask questions like what is the evolutionary relationship between a set of sequences from different species? Or how have certain microbial strains arisen? Blast As any bioscientist probably knows,…
Read More How to Generate High-Quality SNPs Data Sets from NGS
SNPs or single nucleotide polymorphisms are on many scientist’s wish list in experimental studies of genomic DNA sequences. Methods to detect SNPs have evolved. Now with the availability of high throughput sequencing methods, also known as next generation sequencing (NGS), SNPs can be identified in the large amounts of DNA sequence that is generated. There…
Read MoreInvestigating an Expression Quantitative Trait Locus (eQTL)
Thousands upon thousands of genetic variants are now associated with every disease and trait you can possibly think of. Such traits range from cancers to blood pressure, intelligence, height, weight… and many more! This is largely because of the advent of genome-wide association studies (GWAS). However, the vast majority of genetic loci associated with these traits are…
Read More Variations on the ChIP-seq Theme and Challenges of Befriending Large Datasets
ChIP-seq has proved amazing. Through these new techniques, we can obtain big datasets in a matter of days, making our lives in the lab easier and more efficient. ChiP-seq combines chromatin immunoprecipitation (ChIP) assays with whole genome sequencing. This makes it possible to understand where proteins bind to DNA and epigenetic modifications. Humans are not only their…
Read More Genomics Software – Doorways to Visualize Sequence Data
Are you tired of staring at all of your sequence data? Want to know the easiest way to look at it? For complex genomics data, an appropriate visualization tool is a must have. The right genomics software will make it easy-peasy to get some results as well as test all those ideas you have. Since…
Read More Introduction to Linux for High-Throughput Sequencing Analysis
So, you’ve spent time planning your high-throughput sequencing experiment. You’ve chosen how many replicates to use, deliberated about sequencing depth, and kept everything RNase-free. Now you have many gigabytes of data available. What’s next? While the first step of RNA-Seq analysis is aligning your sequencing reads to a reference genome, first you need to get…
Read More How to Follow up on a GWAS (Genome-Wide Association Study)
So, the genome-wide association study (GWAS) data for your disease of interest was published, and it has thrown up some very interesting associations. However, at this stage, bear in mind that this is only an association. Your project is to provide the link between the GWAS single nucleotide polymorphisms (SNP) and pathological changes. Where do…
Read More An Introduction to Shotgun Sequencing: Fire in the Hole
In the midst of all the cool new sequencing techniques and technologies out there today, you may have overlooked the tried and true method of Shotgun Sequencing. What is Shotgun Sequencing Anyway? Shotgun sequencing gets its name from the concept that a large sequence is essentially broken up in to many, many smaller pieces, similar…
Read More How to Choose The Appropriate Genomic NGS Data Simulator
Let’s say that you’ve just finished gathering your NGS reads and you’re going to simulate the introduction of random mutations at specific rates into the reads. Before you move on to the next step, you need to determine which NGS data simulator will get the job done. With the ever-increasing advancement of NGS in the…
Read More P19 to the Rescue: How to Increase Protein Expression in Agroinfiltration
Plants are just not green gods—they can be more. You can cost-effectively express your recombinant complex proteins in a plant system. More interestingly, plants are ideal systems for producing functional monoclonal antibodies, enzymes, and vaccine components! They can also be used for protein localization studies. To save time, you can transiently express your protein using…
Read More The Ins & Outs of Illumina Sequencing
The future of personalized medicine depends on affordable DNA sequencing. In the race for the $1,000 genome, several sequencer manufacturers are working on making equipment that can sequence DNA and RNA faster and more accurately. But so far, only one company – San Diego, California-based Illumina – has US FDA regulatory approval to use its…
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