Sharks evolve at glacial pace, new genetic study confirms
Scientists have directly measured the mutation rate in sharks for the first time, finding it ranks among the lowest of any vertebrate. The discovery explains why sharks struggle to adapt to rapid environmental change—a critical concern as ocean conditions shift and fishing pressure mounts on already vulnerable populations.
Originaltitel: Low mutation rate in epaulette sharks is consistent with a slow rate of evolution in sharks
<p>Sharks occupy diverse ecological niches and play critical roles in marine ecosystems, often acting as apex predators. They are considered a slow-evolving lineage and have been suggested to exhibit exceptionally low cancer rates. These two features could be explained by a low nuclear mutation rate. Here, we provide a direct estimate of the nuclear mutation rate in the epaulette shark (Hemiscyllium ocellatum). We generate a high-quality reference genome, and resequence the whole genomes of parents and nine offspring to detect de novo mutations. Using stringent criteria, we estimate a mutation rate of 7x10-10 per base pair, per generation. This represents one of the lowest directly estimated mutation rates for any vertebrate clade, indicating that this basal vertebrate group is indeed a slowly evolving lineage whose ability to restore genetic diversity following a sustained population bottleneck may be hampered by a low mutation rate. Mutations provide the genetic variability required for evolutionary change. Here, using pedigree-based whole genome sequencing, the authors determine that the Epaulette shark appears to have the lowest mutation rate identified in a vertebrate, providing a potential explanation for slow evolution in the shark lineage.</p>