Genetic Diversity and Population Genetics of Baleen Whales

Baleen whales, as long-lived marine megafauna, harbour genetic signatures of both ancient climatic cycles and recent human-induced pressures. Novel applications of whole-genome sequencing, high-coverage mitogenomics and population modelling have revealed pronounced demographic bottlenecks coincident with industrial whaling, varied recovery trajectories among ocean basins and the key role of low-level migration in sustaining small, isolated groups. Studies across fin, right, bowhead, gray and blue whales have elucidated subspecies boundaries, levels of inbreeding and the extent of genetic drift. Integrating nuclear and mitochondrial markers has clarified population structure, identified lost maternal lineages, and informed adaptive management strategies aimed at preserving genetic resilience under ongoing environmental change.

Research from Nature Portfolio

Whole-genome comparisons of Eastern North Pacific and Gulf of California fin whale populations have quantified the genomic impact of twentieth-century whaling. Analyses of fifty genomes show a severe 99% reduction in effective population size in the Eastern North Pacific during the whaling era, contrasted with a small, stable Gulf of California group. Despite fewer than one migrant per generation, that limited gene flow has been sufficient to maintain viability and prevent runaway inbreeding. Detailed demographic reconstructions and forward simulations demonstrate how historical declines and subsequent connectivity can guide conservation efforts by pinpointing critical thresholds of migration needed for population persistence.

Genetic Diversity and Population Genetics of Baleen Whales publication trend

The graph below shows the total number of articles in genetic diversity and population genetics of baleen whales across all publications each year (not limited to Nature Index journals).

Technical terms

Effective population size: The number of breeding individuals in an idealised population that would show the same genetic drift as the observed population.

Genetic diversity: The variety of alleles and genotypes within a population, reflecting its capacity for adaptation.

Gene flow: The transfer of genetic material between populations through migration or dispersal.

Genomic heterozygosity: The proportion of loci at which an individual carries two different alleles, indicative of overall genetic variation.

Runs of homozygosity: Continuous stretches of identical alleles in an individual’s genome, often arising from recent inbreeding or severe bottlenecks.

References

1. The genomic footprint of whaling and isolation in fin whale populations. Nature Communications (2023).
2. Unraveling the Genetic Legacy of Commercial Whaling and Population Dynamics in Arctic Bowhead Whales and Narwhals. Global Change Biology (2024).
3. A comparison of genomic diversity and demographic history of the North Atlantic and Southwest Atlantic southern right whales. Molecular Ecology (2023).
4. Mitogenomic Phylogenetics of Fin Whales (Balaenoptera physalus spp.): Genetic Evidence for Revision of Subspecies. PLOS ONE (2013).
5. The inference of gray whale (Eschrichtius robustus) historical population attributes from whole-genome sequences. BMC Ecology and Evolution (2018).
6. High genetic diversity in a small population: the case of Chilean blue whales. Ecology and Evolution (2014).