Preface
Metagenomics Definition: The study of metagenomes – genetic material obtained directly from envronmental sample.
Traditionally, a scientist would isolate one species to culture enough DNA for sequencing resulting in the loss of the true biodiversity that existed in the sample.
Shotgun Sequencing (SS)
SS randomly shears DNA, sequences the short fragments, then reassembles these sequences into the correct order – called consensus sequence.
Eukaryotic DNA can be identified and removed, leaving the microbial DNA behind for analysis.
Studies Using Metagenomics
…does each type of mammal have its own community of (gut) microbes?
…the diet of mammals, not the specfic species of that mammal, determines what microorgansms live in the gut.
Metagenomics can also be used as a diagnostic tool to discover causative agents of diseases.
Questions to Consider
- Why is metagnomics used versus traditional genomic techniques?
Traditional science isolated and cultured only the most abundant species, resulting in the loss of the true biodiversity that actually existed in the collected sample, metagenomics allows for determining evolutionary interactions in a particular environment by revealing the hidden biodiversity of microscopic life.
2. Why is shotgun sequencing used in the field of study?
In order to gain knowledge on the true biodiversity of all species in a given environmental sample:
SS takes pieces of DNA and sequences the short fragments into the correct order.
The result is defined as a consensus sequence.
3. Why is metagenomics closely tied to evolutionary biology?
When used as a diagnostic tool, it can be used to discover causative agents of disease, such viral evolution, by filtering out DNA of a healthy species to reveal the disease in a sick subject.
Comment:
I don’t get the explanation of Shotgun Sequencing provided by the author. SS got its name from the broad trajectory of buckshot a shotgun blast produces. Then, SS is likened to putting ten copies of the textbook in a shredder, taking those pieces out and reassembling a complete book.
Without going further, two consecutive metaphors (1 metaphor, 1 simile) leaves a cub-metagenomicist with a rapidly spinning propeller. I think I would try to reconcile the two metaphors before giving an explanation that doesn’t seem to address either. There must be a better definition of Shotgun Sequencing out there.
