A genomic analysis published in the journal Molecular Ecology has confirmed suspicions that two species of North Atlantic sea stars interbreed and thrive from the coasts of New England to Canada. The study presents genomic evidence for hybridization between the species Asterias rubens (common sea star) and Asterias forbesi (Forbes sea star).
This finding is important because it is the first time that evidence of extensive hybridization throughout the genome has been found in an ecologically important coastal species. The researchers collected DNA samples from both species at 33 sites in the North Atlantic and found that hybridization between them is widespread from Cape Cod to Nova Scotia.
The study also found that sea stars have different environmental preferences, which is reflected in their genomes. A. forbesi adapts to local environments with a limited geographical range, while A. rubens has a wider range extending into Western Europe. These differences in environmental preferences have led to the emergence of hybrid zones where the ranges of both species overlap.
The results also suggest that A. forbesi tolerates warmer temperatures better, while A. rubens prefers colder habitats. Hybrids occur in areas where temperatures are tolerable for both species.
These starfish play an important role in the surrounding marine communities and their removal can lead to the collapse of diversity in these ecosystems. Additionally, rising temperatures in the Gulf of Maine, where these sea stars are found, could have significant impacts on their genomic distribution.
This study raises questions about the future of these hybrid species and their ability to adapt to climate change. It is crucial for marine conservation to study these species as they have far-reaching impacts on the rest of the community.