DNA Sequencing Technologies

The term DNA sequencing refers to sequencing methods for determining the order of the nucleotide bases—adenine, guanine, cytosine, and thymine—in a molecule of DNA.

Knowledge of DNA sequences has become indispensable for basic biological research, other research branches utilizing DNA sequencing, and in numerous applied fields such as diagnostic, biotechnology, forensic biology and biological systematics. The advent of DNA sequencing has significantly accelerated biological research and discovery. The rapid speed of sequencing attained with modern DNA sequencing technology has been instrumental in the sequencing of the human genome, in the Human Genome Project. Related projects, often by scientific collaboration across continents, have generated the complete DNA sequences of many animal, plant, and microbial genomes.

The first DNA sequences were obtained in the early 1970s by academic researchers using laborious methods based on two-dimensional chromatography. Following the development of dye-based sequencing methods with automated analysis, DNA sequencing has become easier and orders of magnitude faster.

High-throughput sequencing

The high demand for low-cost sequencing has driven the development of high-throughput sequencing technologies that parallelize the sequencing process, producing thousands or millions of sequences at once. High-throughput sequencing technologies are intended to lower the cost of DNA sequencing beyond what is possible with standard dye-terminator methods

Data from the NHGRI Large-Scale Genome Sequencing Program

The current "Cost per Genome" - the cost of sequencing a human-sized genome is shown on the left. This plot is generated and updated by the National Human Genome Research Institute (NHGRI) (circa February 2011).

The plot includes cost The expenditures included in each category were established based on discussions between NHGRI staff and sequencing center personnel.

Cost per Genome include labor, administration, management, utilities, reagents, and consumables, sequencing instruments and other large equipment (amortized over three years), informatics activities directly related to sequence production (e.g., laboratory information management systems and initial data processing), shotgun library construction (required for preparing DNA to be sequenced).

Costs associated with non-production activities such as data analysis downstream of initial data processing, informatics tools or informatics tool development are not included in these figures.

As of October 2010, the cost of sequencing a genome is $29,092, or 32 cents per megabase of DNA. These numbers are achievable using one of the following instruments with given coverage (number of times a region is sequenced for reliability).

  1. Sanger-based sequencing (average read length=500-600 bases): 6-fold coverage

  2. 454 sequencing (average read length=300-400 bases): 10-fold coverage

  3. Illumina and SOLiD sequencing (average read length=50-100 bases): 30-fold coverage


References:
Wetterstrand KA. DNA Sequencing Costs: Data from the NHGRI Large-Scale Genome Sequencing Program Available at: www.genome.gov/sequencingcosts. Accessed February 6, 2011.

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