Answer: 16s rRNA subunit is an universal target, all bacteria have it, it has conserved regions that allow the design of primers to detect all bacteria, it can also be amplified through variable regions, it is a multicopy gene which increases the detection sensitivity, 16S rRNA genes are easy to obtain from a bacterial isolate.
Explanation:
<u>16S rRNA is the component of the minor subunit (30S) of the prokaryotic ribosomes</u> that binds to the Shine-Dalgarno sequence. The genes that encode it are known as 16S rRNA genes, and <u>it is one of the most studied and characterized gene, used for phylogeny reconstruction and in various databases</u> mainly because of their low rates of evolution. It evolves at relatively constant speeds which allows to infer phylogenetic relationships.
This subunit is an universal target because it is part of the translation process, therefore it is present in all bacteria. Then, since 16S rRNA genes are ubiquitous, there can not be translation without it, so all bacteria have it. It is composed of conserved and variable regions, and these conserved regions allow the design of primers to detect all bacteria. But it can also be amplified through variable regions where the differences in the sequence of the bases allow the determination of several species. Even more so considering that it is a multicopy gene, which increases the detection sensitivity. However, not all the regions are equally good at differentiating between species. Also, because of the complexity of DNA-DNA hybridization, 16S rRNA gene sequencing is used to identify bacteria and assist with differentiating between closely related bacterial species.
16S rRNA genes are easy to obtain from a bacterial isolate, providing information to identify it, through the use of 16S rRNA databases that are available.
