Fig. 4

Results from the ABBA-BABA tests for different possible topologies among gray whales from the eastern and western populations when using the common minke whale as the outgroup. The D-statistic for each topology is considered statistically significant, meaning the topology can be rejected, if the associated standard score (|Z|) has an absolute value > 3. The two gray topologies were both rejected (|Z| > 3), but the black topology could not be rejected (|Z| < 3). This indicates that the signal of contemporary genomic structure we detected among geographic populations is stronger than the signal of historical admixture. WGW, western gray whale. EGW, eastern gray whale