title: Seascape genetics along environmental gradients in the Arabian Peninsula: insights from ddRAD sequencing of anemonefishes.
abstract: Understanding the processes that shape patterns of genetic structure across space is a central aim of landscape genetics. However, it remains unclear how geographical features and environmental variables shape gene flow, particularly for marine species in large complex seascapes. Here, we evaluated the genomic composition of the two-band anemonefish Amphiprion bicinctus across its entire geographical range in the Red Sea and Gulf of Aden, as well as its close relative, Amphiprion omanensis endemic to the southern coast of Oman. Both the Red Sea and the Arabian Sea are complex and environmentally heterogeneous marine systems that provide an ideal scenario to address these questions. Our findings confirm the presence of two genetic clusters previously reported for A. bicinctus in the Red Sea. Genetic structure analyses suggest a complex seascape configuration, with evidence of both isolation by distance (IBD) and isolation by environment (IBE). In addition to IBD and IBE, genetic structure among sites was best explained when two barriers to gene flow were also accounted for. One of these coincides with a strong oligotrophic-eutrophic gradient at around 16-20˚N in the Red Sea. The other agrees with a historical bathymetric barrier at the straight of Bab al Mandab. Finally, these data support the presence of interspecific hybrids at an intermediate suture zone at Socotra and indicate complex patterns of genomic admixture in the Gulf of Aden with evidence of introgression between species. Our findings highlight the power of recent genomic approaches to resolve subtle patterns of gene flow in marine seascapes.
authors.affiliation: Division of Biological and Environmental Science and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.|Instituto de Ciencias Ambientales y Evolutivas, Universidad Austral de Chile, Valdivia, Chile.
authors.forename: Pablo
authors.initials: P
authors.lastname: Saenz-Agudelo
authors.affiliation: Division of Biological and Environmental Science and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.|Department of Environment and Agriculture, Curtin University, PO Box U1987, Perth, WA, 6845, Australia.
authors.forename: Joseph D
authors.initials: JD
authors.lastname: Dibattista
authors.affiliation: Computational Bioscience Research Center, King Abdullah University of Science and Technology, Thuwal, 23955, Saudi Arabia.
authors.forename: Marek J
authors.initials: MJ
authors.lastname: Piatek
authors.affiliation: School of Biological and Biomedical Sciences, Durham University, South Road, Durham, DH1 3LE, UK.|Section of Ichthyology, California Academy of Sciences, 55 Music Concourse Drive, San Francisco, CA, 94118, USA.
authors.forename: Michelle R
authors.initials: MR
authors.lastname: Gaither
authors.affiliation: Australian Research Council Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, QLD, 4811, Australia.
authors.forename: Hugo B
authors.initials: HB
authors.lastname: Harrison
authors.affiliation: Division of Biological and Environmental Science and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.|USR 3278 CRIOBE CNRS-EPHE, CRIOBE BP 1013, Papetoai, 98729, Moorea, French Polynesia.
authors.forename: Gerrit B
authors.initials: GB
authors.lastname: Nanninga
authors.affiliation: Division of Biological and Environmental Science and Engineering, Red Sea Research Center, King Abdullah University of Science and Technology, Thuwal, 23955-6900, Saudi Arabia.
authors.forename: Michael L
authors.initials: ML
authors.lastname: Berumen
mesh_terms: D000818:Animals; D001499:Bayes Theorem; D016000:Cluster Analysis; D004777:Environment; D051456:Gene Flow; D005828:Genetics, Population; D005843:Geography; D019156:Indian Ocean; D016013:Likelihood Functions; D008957:Models, Genetic; D009850:Oman; D010473:Perciformes / Q000235:genetics*; D025341:Principal Component Analysis; D017422:Sequence Analysis, DNA; D015006:Yemen
keywords: empirical; fish; hybridization; landscape genetics; population genetics