Three regional phylogroups in Holarctic Daphnia rosea s.l. Holarctic Neighbor-joining phylogeny based on mitochondrial ND2 sequences of D. rosea s.l. and its closely related species. Numbers on branches indicate bootstrap support. D. rosea s.l. has three geographical groups (Japanese/America, Siberia and Europe). Each individual of two Japanese populations (Kazefuki-o-ike and Hakuba-o-ike, Nagano) had two copies of sequences (connected with a line): one (cross) was a putative pseudogene, which had one stop codon; and stop codons and frameshifts where absent from the other (circle).