Here are diagrams of the mtDNA control region of the round and tubenose gobies. Lines on the round goby diagram denote locations of intraspecific variation. Lines on the tubenose goby diagram denote interspecific differences between the round and tubenose goby genotypes. Note that the tubenose goby control region is much shorter, since it lacks the four tandem repeat sequence blocks of the round goby. Here is a neighbor-joining genetic distance tree showing the haplotypes for the round goby from Eurasian and North American population areas.
Regions are North America versus Eurasian sites.