What To Do When Whole Genome Sequencing Yields Unexpected Results: Is There A One-Size-Fits-All Answer?

Whole genome sequencing (WGS) is becoming increasingly common. Doctors now routinely order it for patients with puzzling diseases. The NHS (National Health Service in the UK) has declared that it will sequence 100,000 genomes over the next few years. Increase WGS…increase ethical questions The direct-to-consumer company 23andme has been experimenting with whole exome sequencing (WES), and another company, DNA…

Galaxy: A Free NGS Workflow Management System

Most ‘wet lab’ biologists do not have much computer programming experience, which can make downstream analysis of next generation sequencing results a bit daunting. After the sequencing platform spits out your data, what do you do with it? That’s where Galaxy comes in. What is Galaxy? Galaxy is a bioinformatics workflow management system, created by collaboration…

Shearing DNA For Next Generation Sequencing: Which Method Should I Choose?

Next-generation sequencing (NGS) really has taken the world by storm! In NGS, millions of short ‘read’s are sequenced in a short space of time, leaving you with vast amounts of data to analyze! For all NGS platforms, the input sample (i.e. your cell free DNA) must be cleaved into short sections or fragments prior to…

Solid Phase Reversible Immobilization: How To Get A Bead On The Clean-up Of Your NGS Libraries

“Any sufficiently advanced technology is indistinguishable from magic.” – Arthur C. Clarke In the fast-moving field of next generation sequencing, standard practices are evolving rapidly. Today, more and more labs are using Solid Phase Reversible Immobilization (SPRI) beads instead of gel purification in the preparation of libraries for sequencing. A crucial step, not for the…

How To Troubleshoot Your DNA Libraries For 454 Next Generation Sequencing- An Essential Guide.

For those of you who prepare your own DNA libraries, this article will cover the most critical aspects of library preparation to ensure a successful sequencing run. Previous Bite Size Bio articles have covered the basics of how 454 sequencing works, so give those a quick review if you are unfamiliar with the process. This video is also highly…

Why Is It Important To Run Your NGS Gels Consistently?

Size Selection via Gel Electrophoresis Whether you are using NGS for whole genome sequencing, SNP variant analysis, HLA typing, HLA matching, or even transcriptome or miRNA analysis by RNA-seq, size selection is an extremely important consideration for optimum results. Precise size selection can increase sequencing efficiency, save money and improve genome assemblies, as well as…

Where Did It All Go Wrong?! Quality Control For Your NGS Data

You’ve carefully collected your samples, extracted nucleic acids and made your first set of next-generation sequencing libraries. How are you going to know if the data you get back is any good and whether it will be worth the effort in learning how to do the analysis? Who is to blame? Fortunately, there are several…

Ignore The Ticking Bomb At Your Peril: RNA-Seq Normalization- A Lurking Problem And It’s Solution.

You have spent days, if not weeks, at the bench setting up the treatment and control samples for that crucial experiment. You submitted your cDNA library for sequencing and after a few weeks of waiting anxiously you get back a list of differentially expressed genes. Hooray?! Hold on- not quite yet! There is something you…

An image of colors to depict care for your pH meter.

A Beginners’ Guide to Non-coding Sequence Alignment

There is no such thing as “junk” DNA Until recently, vast areas of the genome had been denounced as “junk” DNA, because they do not encode proteins. However, it has become clear that these regions have a large diversity of other functions, from transcriptional and translational regulation to the protection of genes and genome integrity….

7 Tips for Preparing Chromatin for ChIP from Tissues (Rather than Cells)

A commonly used technique in epigenetics is Chromatin Immunoprecipitation, or ChIP for short. This technique can show you whether a certain protein (e.g. transcription factor or histone modification) binds to DNA, when in its native conformation, namely chromatin. Insightful, but difficult This information can be very insightful, but difficult to obtain. Most protocols and suggestions…

10 Ways to Improve Your Bisulfite Sequencing Results

10 Ways to Improve Your Bisulfite Sequencing Results

The importance of epigenetics in biology is increasingly acknowledged (if you’re not convinced yet, read my crash course). One commonly studied epigenetic mark is CpG methylation: cytosines that are directly followed by a guanine nucleotide (indicated by CpG), can be methylated, unlike non-CpG Cs. Since attachment of a methyl group to a cytosine can affect…

NGS Quality Control in RNA Sequencing- Some Free Tools

RNA sequencing (‘RNA-seq’) has become one of the most widely used applications for Next-Generation Sequencing. RNA-seq can provide gene expression data more cheaply than microarray, at greater sensitivity, and without the biases inherent in an assay based on quantifying nucleic acid hybridization. RNA-seq can also provide data about alternative splicing, allele-specific expression, expression of non-annotated…

DNA isolation

Garbage in, Garbage out? Quality Control of Your NGS Data

So, you’ve just received a call from the core facility that you hired to prepare and sequence your libraries. The facility director tells you that the sequence data from your next generation sequencing (NGS) experiment does not look good. You panic and, perhaps, let loose a scream of frustration—aaarrrrggghhhh! This project was going to be…

A Short History of Sequencing Part 2: the first of the next.

The Human Genome Project was successful, but hard work. The major improvements to the technology were the increases in parallelization and automation. In 2003, just as the HGP completion papers were published in Nature and Science, ABI launched the‘3730XL’. It could run 24 96-well plates per day and generate around 2 MB of sequence. Some…

A Short History of Sequencing Part 1: from the first proteins to the Human Genome

It all started with proteins The earliest methods for sequencing were developed for proteins. In 1950, Pehr Edman published a paper demonstrating a label-cleavage method for protein sequencing which was later termed “Edman degradation”. Around the same time Fred Sanger was developing his own labelling and separation method which led to the sequencing of insulin….

Sequencing genomes from Neanderthals to James Watson: The Roche 454 Genome Sequencer Explained

A revolution in 2005 The start of the NGS revolution was clearly marked in 2005 by the  publication of the complete genome sequences of two bacterium (Mycoplasma genitalium and Streptococcus pneumonia) by 454 Life Sciences Corporation in one run of their Genome Sequencer with a 96% coverage at 99.96 % accuracy (Margulies et al. 2005)….

How the Ion Torrent Sequencer works

Just before Life Technologies purchased the start-up company Ion Torrent, the fledgling company was dealing with a torrent of another kind—worldwide media interest in its new sequencing technology, which promised to bring the price of next-generation, massively parallel sequencing down to $1,000 per run. Since that dramatic announcement in the summer of 2011, Life Technologies…

Sequencing-by-Synthesis: Explaining the Illumina Sequencing Technology

The “sequencing-by-synthesis” technology now used by Illumina was originally developed by Shankar Balasubramanian and David Klenerman at the University of Cambridge. They founded the company Solexa in 1998 to commercialize their sequencing method. Illumina went on to purchase Solexa in 2007 and has built upon, and rapidly improved the original technology. Millions of reactions and…

Next Generation Sequencing Channel, A Revolution in Technology

Next Generation DNA Sequencing (NGS) is a revolutionary new technology that provides biologists and medical scientists with the ability to collect massive amounts of DNA sequence data both rapidly and cheaply. This technology is having a huge impact on many aspects of biology and medicine because it can be applied in so many different ways….

A Crash Course in Epigenetics Part 4: Disease mechanisms and therapeutic targets

A Crash Course in Epigenetics Part 4: Disease mechanisms and therapeutic targets

After having discussed what epigenetic mechanisms are and how we’ve learnt about what they do, it is now time to look into how epigenetics affect our lives if things do not go the way they are supposed to go. I hope I have convinced you that epigenetic processes are vital for an organism, in development…

A Crash Course in Epigenetics Part 3: Regulated regulation

A Crash Course in Epigenetics Part 3: Regulated regulation

Epigenetics is the most rapidly expanding field in biology. In the second article in this series, I discussed which experimental techniques have been crucial in gaining insight into epigenetic processes. I will now shed light on what those and other methods have taught us. As described in the first article, it has been long understood…

A Crash Course in Epigenetics Part 2: The toolbox of the epigeneticist

A Crash Course in Epigenetics Part 2: The toolbox of the epigeneticist

In the past decade, important advances have been made in the field of epigenetics. Obviously, unraveling epigenetic mechanisms has been greatly facilitated by technological developments. I’ll try to give you an impression of the types of experiments that have helped fuel those new and exciting insights. Yevgeniy Grigoryev has recently written an article on DNA…

A Crash Course in Epigenetics Part 1: An intro to epigenetics

A Crash Course in Epigenetics Part 1: An intro to epigenetics

These days, epigenetics is a fast moving field. I don’t remember having learnt about it during my biomedical studies, some 10 years ago. Nowadays, there seems to be no way around it when studying health and disease. Increasing interest combined with recent technological breakthroughs have led to quickly expanding knowledge of its abundant and important…

An Introduction To ChIP-seq

An Introduction To ChIP-seq

ChIP-seq is a wonderful technique that allows us to interrogate the physical binding interactions between protein and DNA using next-generation sequencing. In this article, I’ll give a brief review of ChIP and introduce the chromatin immunoprecipitation sequencing technique (ChIP-seq), which combines ChIP with next-generation sequencing. What is chromatin immunoprecipitation? Chromatin immunoprecipitation (ChIP) allows us to…