Whale genomes YY

Minke whale genome and aquatic adaptation in cetaceans

Abstract

The shift from terrestrial to aquatic life by whales was a substantial evolutionary event. Here we report the whole-genome sequencing and de novo assembly of the minke whale genome, as well as the whole-genome sequences of three minke whales, a fin whale, a bottlenose dolphin and a finless porpoise. Our comparative genomic analysis identified an expansion in the whale lineage of gene families associated with stress-responsive proteins and anaerobic metabolism, whereas gene families related to body hair and sensory receptors were contracted. Our analysis also identified whale-specific mutations in genes encoding antioxidants and enzymes controlling blood pressure and salt concentration. Overall the whale-genome sequences exhibited distinct features that are associated with the physiological and morphological changes needed for life in an aquatic environment, marked by resistance to physiological stresses caused by a lack of oxygen, increased amounts of reactive oxygen species and high salt levels.

 

      

 

Conclusion

To the best of our knowledge, the minke whale reference genome is the first high-depth marine mammalian genome to be sequenced. The cetacean genomes support hypotheses regarding adaptation to hypoxic resistance, metabolism under limited oxygen and high-salt conditions and the development of unique morphological traits. In particular, the expansion of antioxidant-related genes and whalespecific variations in glutathione-associated and haptoglobin proteins are evidence for adaptation to hypoxic conditions during diving. These data will contribute to future studies of marine mammal diseases, conservation and evolution.