Wild pedigrees inform mutation rates and historic abundance in baleen whales

Phylogeny-based estimates suggesting a low germline mutation rate (mu) in baleen whales have influenced research ranging from assessments of whaling impacts to evolutionary cancer biology. We estimated mu directly from pedigrees in four baleen whale species for both the mitochondrial control region and nuclear genome. The results suggest values higher than those obtained through phylogeny-based estimates and similar to pedigree-based values for primates and toothed whales. Applying our estimate of mu reduces previous genetic-based estimates of preexploitation whale abundance by 86% and suggests that mu cannot explain low cancer rates in gigantic mammals. Our study shows that it is feasible to estimate mu directly from pedigrees in natural populations, with wide-ranging implications for ecological and evolutionary research.