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Population genomic analyses reveal that salinity and geographic isolation drive diversification in a free-living protist

Rengefors, Karin LU ; Annenkova, Nataliia LU ; Wallenius, Joel LU orcid ; Svensson, Marie LU ; Kremp, Anke and Ahrén, Dag LU orcid (2024) In Scientific Reports 14.
Abstract

Protists make up the vast diversity of eukaryotic life and play a critical role in biogeochemical cycling and in food webs. Because of their small size, cryptic life cycles, and large population sizes, our understanding of speciation in these organisms is very limited. We performed population genomic analyses on 153 strains isolated from eight populations of the recently radiated dinoflagellate genus Apocalathium, to explore the drivers and mechanisms of speciation processes. Species of this genus inhabit both freshwater and saline habitats, lakes and seas, and are found in cold temperate environments across the world. RAD sequencing analyses revealed that the populations were overall highly differentiated, but morphological similarity... (More)

Protists make up the vast diversity of eukaryotic life and play a critical role in biogeochemical cycling and in food webs. Because of their small size, cryptic life cycles, and large population sizes, our understanding of speciation in these organisms is very limited. We performed population genomic analyses on 153 strains isolated from eight populations of the recently radiated dinoflagellate genus Apocalathium, to explore the drivers and mechanisms of speciation processes. Species of this genus inhabit both freshwater and saline habitats, lakes and seas, and are found in cold temperate environments across the world. RAD sequencing analyses revealed that the populations were overall highly differentiated, but morphological similarity was not congruent with genetic similarity. While geographic isolation was to some extent coupled to genetic distance, this pattern was not consistent. Instead, we found evidence that the environment, specifically salinity, is a major factor in driving ecological speciation in Apocalathium. While saline populations were unique in loci coupled to genes involved in osmoregulation, freshwater populations appear to lack these. Our study highlights that adaptation to freshwater through loss of osmoregulatory genes may be an important speciation mechanism in free-living aquatic protists.

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author
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organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Scientific Reports
volume
14
article number
4986
publisher
Nature Publishing Group
external identifiers
  • pmid:38424140
  • scopus:85186328392
ISSN
2045-2322
DOI
10.1038/s41598-024-55362-5
language
English
LU publication?
yes
id
02e31456-d16d-4ad4-96cf-d20587dc828b
date added to LUP
2024-03-14 09:54:21
date last changed
2024-04-25 06:30:28
@article{02e31456-d16d-4ad4-96cf-d20587dc828b,
  abstract     = {{<p>Protists make up the vast diversity of eukaryotic life and play a critical role in biogeochemical cycling and in food webs. Because of their small size, cryptic life cycles, and large population sizes, our understanding of speciation in these organisms is very limited. We performed population genomic analyses on 153 strains isolated from eight populations of the recently radiated dinoflagellate genus Apocalathium, to explore the drivers and mechanisms of speciation processes. Species of this genus inhabit both freshwater and saline habitats, lakes and seas, and are found in cold temperate environments across the world. RAD sequencing analyses revealed that the populations were overall highly differentiated, but morphological similarity was not congruent with genetic similarity. While geographic isolation was to some extent coupled to genetic distance, this pattern was not consistent. Instead, we found evidence that the environment, specifically salinity, is a major factor in driving ecological speciation in Apocalathium. While saline populations were unique in loci coupled to genes involved in osmoregulation, freshwater populations appear to lack these. Our study highlights that adaptation to freshwater through loss of osmoregulatory genes may be an important speciation mechanism in free-living aquatic protists.</p>}},
  author       = {{Rengefors, Karin and Annenkova, Nataliia and Wallenius, Joel and Svensson, Marie and Kremp, Anke and Ahrén, Dag}},
  issn         = {{2045-2322}},
  language     = {{eng}},
  month        = {{02}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Scientific Reports}},
  title        = {{Population genomic analyses reveal that salinity and geographic isolation drive diversification in a free-living protist}},
  url          = {{http://dx.doi.org/10.1038/s41598-024-55362-5}},
  doi          = {{10.1038/s41598-024-55362-5}},
  volume       = {{14}},
  year         = {{2024}},
}