The mitochondrial genomes of four cockroaches were sequenced.
The presence of a 71-bp intergenic spacer region between trnQ and trnM was a unique feature in B. dubia, but absent in other.
Ectobiidae and Blaberidae (Blaberoidea) formed a sister clade to Blattidae.
Corydiidae is a sister clade of all the remaining cockroach species.