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Genomic analyses reveal range-wide devastation of sea otter populations.

Authors :
Beichman AC
Kalhori P
Kyriazis CC
DeVries AA
Nigenda-Morales S
Heckel G
Schramm Y
Moreno-Estrada A
Kennett DJ
Hylkema M
Bodkin J
Koepfli KP
Lohmueller KE
Wayne RK
Source :
Molecular ecology [Mol Ecol] 2023 Jan; Vol. 32 (2), pp. 281-298. Date of Electronic Publication: 2022 Jan 17.
Publication Year :
2023

Abstract

The genetic consequences of species-wide declines are rarely quantified because the timing and extent of the decline varies across the species' range. The sea otter (Enhydra lutris) is a unique model in this regard. Their dramatic decline from thousands to fewer than 100 individuals per population occurred range-wide and nearly simultaneously due to the 18th-19th century fur trade. Consequently, each sea otter population represents an independent natural experiment of recovery after extreme population decline. We designed sequence capture probes for 50 Mb of sea otter exonic and neutral genomic regions. We sequenced 107 sea otters from five populations that span the species range to high coverage (18-76×) and three historical Californian samples from ~1500 and ~200 years ago to low coverage (1.5-3.5×). We observe distinct population structure and find that sea otters in California are the last survivors of a divergent lineage isolated for thousands of years and therefore warrant special conservation concern. We detect signals of extreme population decline in every surviving sea otter population and use this demographic history to design forward-in-time simulations of coding sequence. Our simulations indicate that this decline could lower the fitness of recovering populations for generations. However, the simulations also demonstrate how historically low effective population sizes prior to the fur trade may have mitigated the effects of population decline on genetic health. Our comprehensive approach shows how demographic inference from genomic data, coupled with simulations, allows assessment of extinction risk and different models of recovery.<br /> (© 2021 John Wiley & Sons Ltd.)

Details

Language :
English
ISSN :
1365-294X
Volume :
32
Issue :
2
Database :
MEDLINE
Journal :
Molecular ecology
Publication Type :
Academic Journal
Accession number :
34967471
Full Text :
https://doi.org/10.1111/mec.16334