Home > DNA Basics > DNA Sequencing

DNA Sequencing

By: Ian Murnaghan BSc (hons), MSc - Updated: 19 Oct 2018 | comments*Discuss
 
Dna Sequence Sequencing Molecules

DNA sequencing is an important concept although it can be a confusing one. For most of the public, understanding why DNA is important is only one step in learning about DNA and how it affects our lives. To fully get a sense of the relevance of DNA to each of us, however, it helps to know how sequencing works and why it is considered so important.

What Exactly is DNA Sequencing?

The very basic unit of the human genome is a single DNA nucleotide. This nucleotide is extremely small and is made up of minuscule atoms, which creates a challenge for even an advanced microscope to be used for detection. Researchers still, however, need to be able to determine the sequence of bases in DNA that make up the human genome. As such, DNA sequencing has been developed but the process itself is a seemingly complex one.

DNA sequencing involves the determination of the order of DNA bases. You may be wondering what makes these bases so important. In a strand of DNA, there are some simple units known as nucleotides. These nucleotides have a 'backbone' that consists of sugars and a phosphate group. The DNA bases can be one of four kinds and they are attached to these sugars. These bases hold the important and unique genetic information for your body. These bases are:

  • Adenine (A)
  • Thymine (T)
  • Cytosine (C)
  • Guanine (G)

In the Beginning

The very first methods used for DNA sequencing were created in the 1970s. During this decade, researchers were only able to sequence a small number of base pairs, which was a far cry from the number needed to sequence just a single gene and an even more daunting and unlikely task to sequence an entire human genome. By 1990, things had improved somewhat but the number of laboratories able to sequence a hundred thousand bases was still few and far between. Not only that, but the cost of sequencing itself was extremely high and impractical. Fortunately, there have been vast improvements since then, particularly in terms of technological advancement. Better still, automation has made the process much faster and a great deal more practical. Now, individual genes are sequenced on a regular basis and can be done quickly and affordably for laboratories. In fact, some laboratories are sequencing more than a hundred million bases in a given year.

How is DNA Sequencing Performed?

DNA sequencing involves the process of figuring out the precise order of the four bases found in one piece of DNA. What this means is that the DNA is really just a template that is used to create a series of fragments. The fragments differ in length by one base and they are separated by size before the bases are identified, which then effectively recreates the original DNA sequence.

Each person has twenty-three pairs of chromosomes - one copy of the human genome. Because technology has limitations, we are limited in how many bases can be read at one time. Therefore, we can't just read each base from one end of a chromosome to the other. To make it feasible, the chromosome is cut down into smaller fragments.

Why Perform DNA Sequencing?

DNA sequencing is important to apply to the human genome. It allows scientists to sequence genes and genomes. Since there is a limit to how many bases can be sequenced in one experiment, larger DNA molecules - as mentioned - have to be 'broken' into smaller fragments before they can be sequenced and reassembled. To ensure that the sequencing is accurate, researchers also perform the sequencing several times. Clearly, finding just one single gene amongst the seemingly endless strands of DNA that constitute the human genome needs some very powerful equipment! With continued research, it is likely that better tools will be developed to make DNA sequencing much more rapid as well as cheaper and more practical for researchers to complete. In doing so, we will have a better understanding of the base sequences that can tell us important genetic information in one specific segment of DNA. Once genes are identified and analysed from sequence information, scientists can look for mutations that cause disease, thereby providing valuable medical information.

You might also like...
Share Your Story, Join the Discussion or Seek Advice..
[Add a Comment]
why is this sooo long and its hard to understand what this is talking about.
bhad bhabie - 19-Oct-18 @ 5:10 PM
exscuse me my name is mariah and i need my answer for i tell on all of yall.
ugly lil boy - 12-Oct-18 @ 3:36 PM
Am planning to work on a project involving quantification of the Deformed Wing Virus(RNA virus) load in bees. After successfully doing an RNA extraction,cDNA synthesis,RT-PCR using the specific primerto detectand run the gelis sequencing a mandatory step?
kimenyi - 5-Sep-17 @ 9:47 AM
HuneX - Your Question:
Well. Thanks for the information. It helped me to survive our recitation

Our Response:
Gald you found it useful.
ExploreDNA - 20-Aug-15 @ 11:50 AM
Well.... Thanks for the information. It helped me to survive our recitation
HuneX - 19-Aug-15 @ 2:45 PM
Thanks for that education because i have learnt alot ....am also a student
GORDY - 6-Mar-15 @ 6:42 AM
Thanks for your precise information..very much helpful.....I love it
Behabelom - 24-May-14 @ 3:27 AM
Share Your Story, Join the Discussion or Seek Advice...
Title:
(never shown)
Firstname:
(never shown)
Surname:
(never shown)
Email:
(never shown)
Nickname:
(shown)
Comment:
Validate:
Enter word:
Topics
Latest Comments
  • rosygirl4
    Re: DNA Test after Death
    I think someone has done my sis wrong.But she was cremated and she visits saying i was wrong i should have gone for an autopsy.Is there any…
    16 December 2018
  • Shelly
    Re: DNA Test after Death
    I have a 4 yr old daughter I was raped while in a relationship I never told him I was pregnant an then he died how would I get dna from a…
    14 December 2018
  • Ann
    Re: DNA Test after Death
    My father was killed on July 5, 2018. I am is only blood child however he never married my mother. He accepted me as his child. His name was…
    7 December 2018
  • Loopy
    Re: DNA Test after Death
    My birth mother and her sister are identical twins my uncle died and I believed he was my father can I do DNA through the siblings of his
    6 December 2018
  • chains
    Re: An Overview of DNA Functions
    The article is helpful.
    29 November 2018
  • Alonzo Perez
    Re: An Overview of DNA Functions
    All known cellular life and some viruses contain DNA. The main role of DNA in the cell is the long-term storage of information.
    29 November 2018
  • Alex
    Re: How was DNA Discovered?
    The photo-51 that Franklin had discovered showed DNA had been crystallized and a blurred x in the center of the molecule revealed a…
    29 November 2018
  • DLRivers
    Re: An Overview of DNA Functions
    Its good to know how the study of DNA has led to further advancements in medicine and human survival.
    29 November 2018
  • Mclovin
    Re: An Overview of DNA Functions
    it is a good web site to learn about DNA
    29 November 2018
  • david
    Re: An Overview of DNA Functions
    the article was very interesting because i learned how DNA works and how it functions and helps us in our lives
    29 November 2018