What is this site about?
This site is designed to answer all your questions about what is DNA sequencing, why is DNA sequenced, and how is DNA sequenced? This site is a work in progress so if there are any questions you think we should add please don't hesitate to contact us.
What exactly is DNA sequencing?
DNA sequencing is the process of determining the precise order of nucleotide bases in a section of a DNA molecule. This description is not very helpful unless you know what DNA is and how information is encoded in a DNA strand.
Why sequence DNA?
The flippant answer is because we can, however, knowing the sequence of a DNA molecule is incredibly useful is you want to know why a animal, plant or bacteria behaves and looks the way it does. To put it in simple terms the reason we are not plants is because the DNA we have inside our cells has a different order (or sequence) to the DNA in a plant, not because there is anything fundamentally different about our DNA and a plants DNA. From a practical perspective this is very useful because we can use exactly the same methods to sequence plant, or even a bacteria's DNA, as we do to sequencing human DNA.
How is DNA sequenced?
There have been a number of ways invented to sequence DNA. The most common approach used today is called Sanger sequencing and was invented by Fred Sanger of Cambridge University. It is relatively simple method to perform if you have the right equipment and reagents, but is quite hard to describe how it works.
What equipment do I need?
This questions depend on how much of the process of DNA sequencing you want to outsource. The more of the process you outsource to specialized sequencing organizations the less equipment you need but the high the cost (remember even if you don't buy the equipment then they need it). At its simplest all you need to obtain the sequence of a DNA region you are interested in is the equipment to collected the DNA from the source organism. This can be sent to a full service DNA sequencing service laboratory and they will do all the required work. This is commonly the most expensive option and is only recommended if you are fabulously wealth.
What reagents do I need?
Basically to do a DNA sequencing reaction you need three things:
- A purified DNA template.
- An oligonucleotide primer.
- DNA sequencing premix reagent like BigDye™ (Applied Biosystems) or DYnamic ET (Amersham).
Generally the critical components is the DNA template. Ideally it should be free of contaminating components like salts, proteins, RNA, polysaccharides and other unrelated DNA species like genomic DNA. It should also be of consistent concentration and not damaged but shear forces, UV light, or endo- or exonucleases.
What software do I need?
You need three pieces of software
- Software to collect the sequencing instrument data.
- Software to convert the instrument data into a nucleotide base order.
- Software to analyze the resulting nucleotide sequence.
What is DNA sequence data used for?
What does DNA sequence data look like?
What DNA sequence data looks like depends on what stage in the process of sequencing it is at. The first state is the raw data as it is collected off the DNA sequencing instrument (Figure 1).
Other useful sequencing sites?
Nucleics has a guide to troubleshooting DNA sequencing problems. Nucleics also has a series of reviews on DNA service providers, that cover such things a cost, sample requiremetns, equipment usedm services provided, turn around times, contact details, etc which is very helpful if you are looking for someone to sequence your DNA samples.
How do I link to this site?
Here are two text links you can cut and paste. Please feel free to edit them to suit your site requirements.
<a href="http://www.dna-sequencing.net">What is DNA sequencing? Why sequence DNA? How is DNA sequenced</a> All your questions answered about what, why & how DNA is sequenced.
<a href="http://www.dna-sequencing.net">What is DNA sequencing?</a> - All about DNA sequencing.