Board Thread:Questions and Answers/@comment-67.233.246.186-20130619145624/@comment-25085317-20140807152959

Technically the DNA of all the alien species selected is present in the Codon Stream and scanning them only unlocks them but you should also remember Destroy All Aliens where the Omnitrix says the primary intelligent species on Earth to be humans and doesn't name the Reptile Leader or chickens so it might mean that Azmuth didn't put their DNA in the Codon Stream, so no DNA in the Codon Stream and no capture mode activation, its that simple.