Data from: Seascape genetics along environmental gradients in the Arabian Peninsula: insights from ddRAD sequencing of anemonefishes

Understanding the processes that shape patterns of genetic structure across space is a central aim of landscape genetics. However, it remains unclear how geographic 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 geographic 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 an historical bathymetric barrier at the straight of Bab al Mandab. Finally, these data support the presence of inter-specific 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.

阐明塑造空间遗传结构模式的过程是景观遗传学（landscape genetics）的核心目标之一。然而，目前仍不清楚地理特征与环境变量如何塑造基因流，对于大型复杂海洋景观中的海洋物种而言这一问题尤为突出。本研究针对分布于红海与亚丁湾全地理分布范围内的双带海葵鱼（Amphiprion bicinctus），以及分布于阿曼南部海岸的特有近缘种阿曼海葵鱼（Amphiprion omanensis）的基因组组成展开了评估。红海与阿拉伯海均为结构复杂、环境异质性显著的海洋系统，为解答上述问题提供了理想的研究场景。研究结果证实了此前针对红海双带海葵鱼所报道的两个遗传簇的存在。遗传结构分析揭示了复杂的海洋景观格局，同时存在距离隔离（Isolation by Distance, IBD）与环境隔离（Isolation by Environment, IBE）现象。除距离隔离与环境隔离外，当同时考虑两个基因流障碍时，样点间的遗传结构可得到最佳解释。其中一个障碍与红海约16°N至20°N处显著的贫营养-富营养梯度相吻合；另一个则与曼德海峡（Bab al Mandab）处的历史水深屏障一致。此外，本研究数据支持在索科特拉岛的中间接合带存在种间杂交个体，并证实亚丁湾存在复杂的基因组混合模式，且存在物种间的基因渐渗现象。本研究结果彰显了新兴基因组学方法在解析海洋景观中微妙基因流模式方面的应用潜力。