A study of the human gut performed in 1982 used various types of plates under different growth conditions to describe and enumerate the microbes in the human gut. They concluded that the majority of the microbes in the human gut are Gammaproteobacteria. A study conducted in 2010 using next-generation sequencing to characterize 16S rRNA sequences concluded that the majority of the microbes in the human gut are Firmicutes and Bacteriodetes. Why did these studies have different conclusions? Which study do you think is most accurate?

In 1982 different technique was used to identify the gut microflora. In 1982 clone libraries were used as a template to identify the sequence of the amplified gene of gut microflora. The amplified target gene was having different genes mixture so there are chances to get the wrong sequence result if they are not separated properly.

16S rRNA is conserved in almost all the bacteria so 16S rRNA sequencing is a better technique to identify bacterial species. Therefore the conclusions is different because the technique used in 1982 was more complicated which was having loopholes so the study in 2010 done by characterizing the 16S rRNA sequence is more accurate.