Contrasting genetic diversity and structure between endemic and widespread damselfishes are related to differing adaptive strategies

Vanessa S. N. Robitzch Sierra, Pablo Saenz-Agudelo, Tilman J. Alpermann, Bruno Frédérich, Michael L. Berumen

Research output: Contribution to journalArticlepeer-review

3 Scopus citations


Aim Several marine biogeographical provinces meet at the Arabian Peninsula. Where and how these junctions affect species is poorly understood. We herein aimed to identify the barriers to dispersal and how these shape fish populations, leading to differing biogeographies despite shared habitat and co-ancestry. Taxon Dascyllus marginatus (endemic) and Dascyllus abudafur (widespread). Location Coral reefs from the Red Sea (RS), Djibouti, Yemen, Oman, and Madagascar. Methods We tested potential barriers to gene flow using RADseq-derived SNPs and identified whether population genetic differences on each side of these barriers were neutral or selective to relate this to the biogeography of the species. Seven locations (ranging over 5100 km) were sampled for the endemic and six (ranging over 7400 km) for the widespread species, taking 20 individuals per location, with two exceptions. Results Dascyllus marginatus populations (comprising 5648 SNPs) had an order of magnitude higher genetic differentiation compared to D. abudafur (comprising 10,667 SNPs), as well as several outlier loci that were absent in D. abudafur despite equal sampling locations. In both species, the RS and Djibouti specimens formed one genetic cluster separated from all other locations. Although ranging from the RS to Madagascar, D. abudafur was absent in Yemen and Oman. Main Conclusions Stronger genetic structure at smaller geographical scales and outlier loci in the endemic species seem associated with faster adaptation to environmental differences and selective pressure. Genetic differentiation in the widespread species is neutral and only occurs at large geographical distances. Restrictive transitions (between the Gulf of Aqaba and the RS or the RS and the Gulf of Aden) do not hinder gene flow in either species, and the environmental shift within the RS (at 22°N/20°N) only affected the endemic species. The genetic break in the Gulf of Aden likely reflects historical colonization processes and not contemporary environmental regimes.
Original languageEnglish (US)
JournalJournal of Biogeography
StatePublished - Nov 24 2022

Bibliographical note

KAUST Repository Item: Exported on 2022-11-28
Acknowledgements: For logistics and fieldwork support in Saudi Arabia, we thank the Coastal and Marine Resources Core Lab at KAUST, the R/V Thuwal crew, diverse dive buddies and Amr Gusti. Sampling permits were obtained from the relevant authorities. Logistical support in Oman was provided by Oli Taylor (Five Oceans Environmental Service, Oman), Kaveh Samimi-Namin (Naturalis Biodiversity Center, Netherlands) and Michel Claereboudt (Sultan Qaboos University). The Ministry of Environment and Climate Affairs of Oman granted collection and export permits. In Madagascar, sampling was approved by and under the supervision of the ‘Institut Halieutique et des Sciences Marines’ of Toliara and took place before the Nagoya protocol. Along the Yemeni mainland, sampling was carried out by Aref Hamoud and Moteah Shaikh. In Socotra, Mohamed Ahmer and Fouad Naseeb (Environmental Protection Authority) supported this research in the frame of the Memorandum Agreement on Scientific and Technical Cooperation. We further thank the Grunelius-Moellgaard Laboratory at the Senckenberg Research Institute and the Natural History Museum in Frankfurt (SMF); the Bioscience Core Laboratory at KAUST for next-generation Illumina sequencing; and CONICYT/Fondecyt N° 1190710 for access to high-performance computers at the UACh. Additional funding came from the KAUST baseline funds to M.L.B. and Xabier Irigoyen, and from LOEWE (Landes-Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz) to Fareed Krupp and Uwe Zajonz (SMF and the Senckenberg Biodiversity and Climate Research Institute).

ASJC Scopus subject areas

  • Ecology
  • Ecology, Evolution, Behavior and Systematics


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