Wild pedigrees inform mutation rates and historic abundance in baleen whales

Phylogeny-based estimates suggesting a low germline mutation rate (μ) in
baleen whales have influenced research ranging from assessments of whaling
impacts to evolutionary cancer biology. We estimated μ 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 μ reduces
previous genetic–based estimates of pre-exploitation whale abundance by
86% and suggests that μ cannot explain low cancer rates in gigantic
mammals. Our study shows that it is feasible to estimate μ directly from
pedigrees in natural populations, with wide-ranging implications for
ecological and evolutionary research.