Jenna M. Lang edited Organism Identification using 16s rRNA gene sequence.md  about 9 years ago

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##Choosing an organism to sequence  JENNA WILL EXPAND THIS SECTION A choice of whether to sequence an organism based on these results depends on the project goal. For example, How closely your isolate is related to  an identity organism with a sequenced genome might be completely irrelevant if you are interested in sequencing your isolate per se, perhaps because  of 100% suggests that at least at where you found it or because of some interesting phenotype. If your goal is to increase  the 16S level, phylogenetic diversity of available genome sequences, then sequencing  the candidate organism 200th E. coli genome  is very similar not the ideal approach  to what is already in achieve that goal. At  the database. However, many organisms vary greatly in gene content between strains and other extreme, if you have isolated  an additional genome may still organism that is only 80% identical to anything with a currently available genome, or that appears to  be informative. The alone on a long branch on your phylogenetic tree, then you have a good candidate to achieve your goal. Of course 80% is arbitrary, as is a “long” branch, but the current standard is to  use of a 97%  16S rRNA gene sequencepercent  identity as a proxy for species delimitation in bacteria bacteria. This is yet another arbitrary cutoff, and  is frequently debated in the field (\cite{Chan_2012}\cite{Drancourt_2005}\cite{Hanage_2006}\cite{Stackebrandt_2002}. Finally, you might be interested in increasing the genome sequences available for  a subject of some debate particular lineage, for example, to provide additional data for a comparative genomics project. In that case, and  in many others, the ideal number of close relatives and  the field. \cite{Chan_2012}\cite{Drancourt_2005}\cite{Hanage_2006}\cite{Stackebrandt_2002}. definition of “close,” will be unique to each project.