3.3.2 Treemix
The genetic relationship visualized using TREEMIX (Fig. 2D) indicated that all of the NA blue whales were allied and distinct from the Antarctic blue whale. The NEA and the NWA blue whales formed a single group. Four of the NWA blue whales (NW-M6, NWa-R4, NWa3 and NWa4) were more closely related to each other than to the other NA blue whales. The Antarctic blue whale did not share significant alleles with any of the present-day NA whales as indicated from the lack of migration events between the Antarctic and any of the NA blue whales. The migration events show gene flow between NW-M6 to NW9 and NE-Ar to NE71, which indicates that blue whales share more alleles with individuals within the same geographic regions. The gene flow indicated by the migration events between the whales were also confirmed using D-statistics.