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Complex Origins and History of the Relict Fennoscandian Ringed Seals
Morten Tange Olsen1,2, Ari Löytynoja3, Mia Valtonen4
1Section for Molecular Ecology and Evolution, Globe Institute University of Copenhagen Copenhagen K Denmark.
Ecology and Evolution
|March 5, 2025
Summary
Fennoscandian ringed seals have a complex evolutionary past, with origins predating the Last Glacial Maximum and multiple colonization events. This genetic diversity is crucial for conservation efforts.
Area of Science:
- Evolutionary biology
- Genetics
- Conservation science
Background:
- Ringed seals inhabit Arctic and isolated Fennoscandian populations (Baltic Sea, Lake Saimaa, Lake Ladoga).
- Previous research suggested a single post-Last Glacial Maximum (LGM) colonization for Fennoscandian seals, but this is now debated.
Purpose of the Study:
- To investigate the phylogeographic complexity and diversification patterns of Fennoscandian ringed seals.
- To clarify the evolutionary history and origins of Saimaa, Ladoga, and Baltic Sea ringed seal populations.
Main Methods:
- Analysis of 246 mitogenomes.
- Examination of 180 skulls for morphological diversity.
Main Results:
- Evidence of pre-LGM diversification from Arctic ringed seals and multiple Fennoscandian colonization events.
- Saimaa seals diverged from Arctic seals before entering Lake Saimaa; Ladoga seals show Arctic origins with secondary Baltic Sea influence; Baltic seals have mixed origins.
- Lake Saimaa and Ladoga seals exhibit reduced genetic diversity and distinct skull morphologies, unlike the diverse Baltic seals.
Conclusions:
- Fennoscandian ringed seals possess a complex evolutionary history, challenging prior assumptions.
- Saimaa, Ladoga, and Baltic ringed seals warrant classification as distinct taxa.
- Conservation strategies must address human impacts and climate change for these unique populations.
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