Data from: Genetic relatedness does not retain spatial pattern across multiple spatial scales: dispersal and colonization in the coral, Pocillopora damicornis

Patterns of isolation-by-distance are uncommon in coral populations. Here, we depart from historical trends of large-scale, geographic genetic analyses by scaling down to a single patch reef in Kāne‘ohe Bay, Hawai‘i, and map and genotype all colonies of the coral, Pocillopora damicornis. Six polymorphic microsatellite loci were used to assess population genetic and clonal structure and to calculate individual colony pairwise relatedness values. Our results point to an inbred, highly clonal reef (between 53 and 116 clonal lineages out of 2352 genotyped colonies) with a very skewed genet frequency distribution (over 70% of the reef was composed of just seven genotypes). Spatial autocorrelation analyses revealed that corals found close together on the reef were more genetically related than corals further apart. Spatial genetic structure disappears, however, as spatial scale increases and then becomes negative at the largest distances. Stratified, random sampling of three neighbouring reefs confirms that reefs are demographically open and inter-reef genetic structuring was not detected. Attributing process to pattern in corals is complicated by their mixed reproductive strategies. Separate autocorrelation analyses, however, show that the spatial distribution of both clones and non-clones contribute to spatial genetic structure. Overall, we demonstrate genetic structure on an intra-reef scale and genetic panmixia on an inter-reef scale indicating that, for P. damicornis, small- and large-scale dispersal processes are likely not the same. By starting from an inter-individual, intra-reef level before scaling up to an inter-reef level, this study demonstrates that isolation-by-distance patterns for the coral P. damicornis are limited to small scales and highlights the importance of investigating genetic patterns and ecological processes at multiple scales.

距离隔离（Isolation-by-distance）模式在珊瑚种群中并不常见。本研究跳出以往大规模地理遗传分析的传统研究范式，将研究尺度缩小至夏威夷卡内奥赫湾（Kāne‘ohe Bay）内的一处斑块礁（patch reef），对该礁体上所有的鹿角杯形珊瑚（*Pocillopora damicornis*）珊瑚群体开展绘图与基因分型工作。我们选用6个多态微卫星（microsatellite）位点，对其种群遗传结构与克隆结构进行评估，并计算所有珊瑚群体间的成对亲缘关系值。研究结果表明，该礁体为近交程度较高、高度克隆化的种群：在完成基因分型的2352个珊瑚群体中，共存在53至116个克隆谱系，且基株频率分布极不均衡——超过70%的礁体仅由7种基株构成。空间自相关（Spatial autocorrelation）分析结果显示，礁体上空间距离较近的珊瑚个体，其遗传亲缘关系显著强于距离较远的个体。不过，空间遗传结构会随空间尺度的增大而逐渐消失，在最大距离尺度下甚至呈现负相关关系。对3处相邻礁体开展的分层随机抽样证实，各礁体的种群统计均呈开放状态，未检测到礁间遗传结构。由于珊瑚兼具混合繁殖策略，将生态过程归因于其遗传模式的研究较为复杂。但分别针对克隆与非克隆个体开展的自相关分析显示，二者的空间分布均对空间遗传结构存在贡献。总体而言，本研究证实了鹿角杯形珊瑚在礁内尺度存在遗传结构，而礁间尺度则呈现随机交配（Panmixia）现象，表明该物种的小尺度与大尺度扩散过程可能并不一致。本研究从个体间、礁内尺度出发，再拓展至礁间尺度，证实了鹿角杯形珊瑚的距离隔离模式仅局限于小尺度范围，并强调了多尺度下开展遗传模式与生态过程研究的重要性。