Multiple independent losses of sporulation and peptidoglycan in the and related orders of the class .

Many peptidoglycan-deficient bacteria such as the are known host-associated lineages, lacking the environmental resistance mechanisms and metabolic capabilities necessary for a free-living lifestyle. Several peptidoglycan-deficient and non-sporulating orders of interest are thought to be descended from Gram-positive sporulating through reductive evolution. Here we annotate 2650 genomes belonging to the class , according to the Genome Taxonomy Database, to predict the peptidoglycan and sporulation phenotypes of three novel orders, , and , known only through environmental sequence surveys.