Very simply, when using metagenomics, distinctions between bacterial species are based upon what?

Metagenomics is the study of genetic material recovered directly from environmental sample. Its field has been responsible for substantial advances in microbial ecology, evolution, and diversity over the past 5 to 10 years and many research laboratories are actively engaged in it now. Using metagenomics, the distinctions between bacterial species are based upon the comparison of DNA nucleotide sequences of different bacterial species.