What is shotgun sequencing

In the group Monocots, the sequencing projects on five organisms are listed. For barley, the project focused on sequencing ESTs only. For rice, the project focused on sequencing both ESTs and the entire genome, and map-based sequencing was completed in For sorghum, the project focused on sequencing both ESTs and the entire genome, and whole-genome shotgun was scheduled to begin in For wheat, the project focused on sequencing ESTs only.

For maize, the project focused on sequencing both ESTs and the entire genome, and map-based sequencing was announced. For the conifers group, two organisms are being sequenced: Pinus and Gnetum.

In the club moss group, there is a sequencing project for the organism Selaginella. This project focused on sequencing both ESTs and the entire genome, and whole-genome shotgun was underway. In the moss group, there is a sequencing project for the organism Physcomitrella. In the green algae group, there is a sequencing project for the organism Chlamydomonas.

This project focused on sequencing the entire genome, and whole-genome shotgun was completed in Figure 2. Platypus Puzzle. Lessons Learned. Figure 3: Evolution of vertebrate genomes. The evolutionary tree shows relationships, times of divergence, and genome sizes in picograms of DNA, pg of vertebrates whose genomes have been selected for sequencing.

Classically, 1 pg of DNA has been considered equivalent to roughly 1 billion base pairs. Used with permission. Gallus gallus domestic fowl and Danio rerio Zebrafish were some of the first organisms to diverge from their respective lineages within this set of animals.

The greatest amount of divergence occurred in the late Mesozoic and Cenozoic eras between 10 and million years ago, when current species developed. In the mammalian group, genetic divergence caused the development of Homo sapiens humans , Pan troglodytes common chimpanzee , Macaca mulatta rhesus macaque , Mus musculus house mouse , Rattus norvegicus Norway rat , Canis familiaris domestic dog , Felis catus domestic cat , Equus caballus horse , Sus scrofa domestic pig , Bos taurus domestic cattle , and Ovis aries domestic sheep.

In the amphibian group, genetic divergence caused the development of Xenopus laevis African clawed frog and Xenopus tropicalis Tropical clawed frog. In the fish group, genetic divergence caused the development of Oryzias latipes Japanese medaka , Tetraodon nigroviridis spotted green pufferfish , and Takifugu rubripes tiger pufferfish.

The bar graph to the right of each organism displays its haploid genome mass in picograms of DNA. The spotted green pufferfish and tiger pufferfish have the smallest haploid genome masses, with values of approximately 0. Domestic cattle have the largest haploid genome mass, with a value of 3.

The haploid genome masses of humans, chimpanzees, and rhesus macaques are approximately 3. References and Recommended Reading Adams, M. Nature , — link to article Bevan, M. The mouse genome. Nature , — link to article Rubin, G. Article History Close. Share Cancel. Revoke Cancel. Keywords Keywords for this Article. Save Cancel. Flag Inappropriate The Content is: Objectionable. Flag Content Cancel. Email your Friend. Submit Cancel. This content is currently under construction. Explore This Subject.

Comparative Genomics. Genome Sequencing and Annotation. Functional Genomics. Translational Genomics. Topic rooms within Genomics Close. No topic rooms are there.

Smith Genomics. Or Browse Visually. Other Topic Rooms Genetics. Student Voices. Creature Cast. Simply Science. Green Screen. Green Science. Bio 2. The Success Code. Why Science Matters. The Beyond. Plant ChemCast. Postcards from the Universe. Brain Metrics. Mind Read. Shotgun sequencing is a laboratory technique for determining the DNA sequence of an organism's genome.

The method involves breaking the genome into a collection of small DNA fragments that are sequenced individually. A computer program looks for overlaps in the DNA sequences and uses them to place the individual fragments in their correct order to reconstitute the genome. The most efficient way to sequence a large piece of DNA involves a process known as shotgun sequencing. Large, mammalian genomes are particularly difficult to clone , sequence and assemble because of their size and structural complexity.

As a result clone-by-clone sequencing, although reliable and methodical, takes a very long time. With the emergence of cheaper sequencing and more sophisticated computer programs, researchers have therefore relied on whole genome shotgun sequencing to tackle larger, more complex genomes. Genome sequencing can mean sequencing an organism's entire genome or just focusing on sequencing very specific areas of DNA. This flash animation shows the processes involved in the Sanger sequencing method — the DNA sequencing method used during the Human Genome Project.

If you have any other comments or suggestions, please let us know at comment yourgenome. Can you spare minutes to tell us what you think of this website? Open survey. In: Facts Methods and Technology. Shotgun sequencing was originally used by Fred Sanger and his colleagues to sequence small genomes such as those of viruses and bacteria.

Whole genome shotgun sequencing bypasses the time-consuming mapping and cloning steps that make clone-by-clone sequencing so slow. In whole genome shotgun sequencing the entire genome is broken up into small fragments of DNA for sequencing. These fragments are often of varying sizes, ranging from kilobases 2,, base pairs to kilobases ,, base pairs.

The sequenced fragments are then assembled together by computer programs that find where fragments overlap. You can imagine shotgun sequencing as being a bit like shredding multiple copies of a book which in this case is a genome , mixing up all the fragments and then reassembling the original text genome by finding fragments with text that overlap and piecing the book back together again.

This method of genome sequencing was used by Craig Venter, founder of the private company Celera Genomics, to sequence the human genome.