DNA Sequence Assembly

DNA sequence assembly is a process that involves aligning and merging fragments of a DNA sequence to reconstruct the original structure of the DNA. This is an essential step of the genome analysis process because the entire genome cannot be interpreted in one step with current sequencing technology. Instead, small sections of the genome with up to 30,000 nucleotide bases are read at once and then assembled to reform the DNA.

How to sequence the human genome - Mark J. Kiel

Assembly is a difficult task because there are often many different fragments of the genome, which need to be pieced back together in the correct order to make sense of the information. There is also some propensity for error in the assembly process due to the repetition of the nucleotide bases in the genome, which may increase the difficulty of assembling the fragments together correctly.

Alignment of fragments

In order to achieve the correct DNA sequence assembly, it is necessary to read multiple fragments of sequences and then link them back together in the correct order. This involves overlapping the ends of the fragments because the current DNA sequencing technology is unable to read the entire genome sequence at once.

The correct alignment of the DNA segments is essential to ensure that the DNA is assembled to form the original. This ensures that understanding taken from the analysis of the genome is relevant and may be able to provide an appropriate use in practice.

A genome is defined as finished when there is a single continuous sequence of DNA with clearly defined nucleotide bases at each point. There should not be any ambiguity as to the replicons in the sequence.


There are two broad types of assembly techniques that may be utilized: de novo and comparative assembly.

De novo assembly is used for new genomes that have not been previously sequenced or are not similar to genomes that have previously been sequenced. This type of assembly is usually harder to conduct due to computational difficulties.

Comparative, or mapping, assembly is used for genomes that have an existing sequence, or have a genome that is similar to another organism that already has an assembled genome, which can be used as a reference.

Assembler technology

The first sequence assemblers to align DNA fragments with automated sequencing instruments were introduced in the early 1980s. Over time, the technology to assemble DNA sequences has evolved considerably as the progression in genomics research have required more sophisticated techniques to manage the information of the genome project underway.

Computing clusters are used with terabytes of sequencing data to assemble the DNA. Identical or very similar sections of the DNA, referred to as repeats, can confound the process and increase the time and complexity of the algorithms required for assembly. Additionally, if there are any minor errors in the DNA fragments due to incorrect calibration of the sequencing instruments or another factor, it can be very difficult to identify the error in the data and exclude the fragment from the results.

There are currently new technologies being developed to help improve the process of DNA assembly. It is hoped that these will contribute to improving the ease and speed of DNA sequence assembly in the future so that the results can be used in practical applications.


  1. http://www.nature.com/nrg/journal/v14/n3/full/nrg3367.html
  2. https://www.hyundai.com/worldwide/en/
  3. https://academic.oup.com/nar/article/23/24/4992/2400677/A-new-DNA-sequence-assembly-program
  4. https://aaai.org/
  5. https://santafe.edu/

Further Reading

Last Updated: Jul 22, 2023

Yolanda Smith

Written by

Yolanda Smith

Yolanda graduated with a Bachelor of Pharmacy at the University of South Australia and has experience working in both Australia and Italy. She is passionate about how medicine, diet and lifestyle affect our health and enjoys helping people understand this. In her spare time she loves to explore the world and learn about new cultures and languages.


Please use one of the following formats to cite this article in your essay, paper or report:

  • APA

    Smith, Yolanda. (2023, July 22). DNA Sequence Assembly. News-Medical. Retrieved on June 25, 2024 from https://www.news-medical.net/life-sciences/DNA-Sequence-Assembly.aspx.

  • MLA

    Smith, Yolanda. "DNA Sequence Assembly". News-Medical. 25 June 2024. <https://www.news-medical.net/life-sciences/DNA-Sequence-Assembly.aspx>.

  • Chicago

    Smith, Yolanda. "DNA Sequence Assembly". News-Medical. https://www.news-medical.net/life-sciences/DNA-Sequence-Assembly.aspx. (accessed June 25, 2024).

  • Harvard

    Smith, Yolanda. 2023. DNA Sequence Assembly. News-Medical, viewed 25 June 2024, https://www.news-medical.net/life-sciences/DNA-Sequence-Assembly.aspx.


The opinions expressed here are the views of the writer and do not necessarily reflect the views and opinions of News Medical.
Post a new comment

While we only use edited and approved content for Azthena answers, it may on occasions provide incorrect responses. Please confirm any data provided with the related suppliers or authors. We do not provide medical advice, if you search for medical information you must always consult a medical professional before acting on any information provided.

Your questions, but not your email details will be shared with OpenAI and retained for 30 days in accordance with their privacy principles.

Please do not ask questions that use sensitive or confidential information.

Read the full Terms & Conditions.

You might also like...
New weapon against cancer: "DNA warhead" targets mutant protein in tumor cells