deletions | additions       diff --git a/16S rDNA Sequencing and Analysis (Organism Identification).md b/16S rDNA Sequencing and Analysis (Organism Identification).md  index d7c9be9..4c77986 100644  --- a/16S rDNA Sequencing and Analysis (Organism Identification).md  +++ b/16S rDNA Sequencing and Analysis (Organism Identification).md 
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The samples can be prepared for 16S rDNA PCR via direct PCR (using the liquid culture as the template for the PCR reaction) or following DNA extraction. Direct PCR significantly decreases the amount of work needed for preparation, but it can yield poorer Sanger results, both in terms of PCR success and resultant sequence quality. We recommend direct PCR when screening a large number of samples. DNA extraction can then be used for any recalcitrant samples. DNA extraction is significantly more work, but it often generates better Sanger sequences allowing for more accurate identification.  ##DNA Extraction  Depending on available equipment, experience, and cost there There  are a number of different options for DNA extraction. The isolation and which one should use depends on many factors including available equipment, experience, and cost. A standard approach in microbiology involves the  use of Phenol-chloroform phenol and chloroform extraction  followed by ethanol precipitation is a microbiology standard, precipitation,  and any number of protocols for this method approach  can be found in books, articles and  on the internet. There are several advantages A common alternative approach is  to using use  a commercially available kit for this purpose, - there are many advantages to such kits -  notably ease and lack of harmful chemicals, but toxic chemicals. A disadvantage of kits is that  they typically are more expensive and per sample than other approaches (especially if one is only doing a few samples since most kits  include reagents materials  for at least a minimum  50 samples. Our lab uses samples). For most projects, we use kits - especially  the Promega-Wizard Genomic DNA Purification Kit or the MO BIO-Power Soil DNA Isolation Kit Kit.  Follow the protocol or kit instructions provided by the manufacturer and then proceed to "PCR reaction" below.