Dispersal of corals on isolated reefs in Western Australia

Ecologically relevant distances of dispersal were inferred from DNA microsatellite data from broadcast-spawning (Acropora tenuis) and brooding (Seriatopora hystrix) corals at isolated reef systems of Western Australia.576 colonies of the broadcast-spawning coral Acropora tenuis were collected from the Rowley Shoals and Scott Reef systems, and 476 colonies of the brooding coral Seriatopora hystrix were collected from the Rowley Shoals, Scott Reef, and Browse Island. Replicate sites were sampled at most reefs within each system, and samples were collected from the reef slope at the Scott Reef system in January 2004, Rowley Shoals in April 2005, and Browse Island in September 2006. The data for Seriatopora hystrix include 287 individuals genotyped from Scott Reef (see another metadata record for details). At each site (except the two at Browse Island), the exact locations of the sampled colonies relative to a 300 m transect were recorded, along with the GPS coordinates at the beginning of each transect.For Seriatopora hystrix, a total of 8 pairs of colonies sampled from the same site shared the same genotype, compared with 7 pairs for Acropora tenuis. One individual from each of these pairs was removed from the subsequent analysis, resulting in between 21 and 50 individuals analyzed at each site. Details of the microsatellite markers recorded were: the number of alleles (A), the proportion of observed (HO) and expected (HE) heterozygotes per locus and site, and the FIS calculated for each locus and each site (FIS All loci). Averages were also calculated for allele (A All loci), expected heterozygosity for all loci at each site (He All loci), expected heterozygosity across all sites (He All sites); as well as the number of private alleles at each site (Pva), the total number of alleles (Atotal) and arithmetic mean of alleles per locus across sites (Amean). The loci names use a prefix for the species followed by 2, 3, 4 or 5 according to the repeat motif type (di-, tri-, tetra- or pentamer), followed by a number: Sh2-002, Sh2-006, Sh3-003, Sh3-004, Sh3-007, Sh3-008, Sh3-009, Sh4-001 (Seriatopora hystrix); Amil2-006, Amil2-010, Amil2-011, Amil2-012, Amil2-018, Amil2-022, Amil5-028 (Acropora tenuis). Congruent with expectations based on life histories, levels of genetic subdivision among populations were markedly higher in the brooder than in the broadcast spawner. Additionally, significant subdivision for both species between systems (>100 km), and between (>10 km) or within reefs (To gain further insight into degree of isolation, effective population size and the importance of asexual versus sexual reproduction, genetic and genotypic (clonal)diversities vary between the high-latitude, offshore reefs and the low latitude, coastal reefs were tested.

本研究基于西澳大利亚孤立礁体系统中广播产卵型细枝鹿角珊瑚（Acropora tenuis）与育幼型盔形梳状珊瑚（Seriatopora hystrix）的DNA微卫星数据，推断了具有生态学意义的扩散距离。研究共采集细枝鹿角珊瑚样本576株，采集自罗利沙洲（Rowley Shoals）与斯科特礁（Scott Reef）系统；盔形梳状珊瑚样本476株，采集自罗利沙洲、斯科特礁及布鲁尔岛（Browse Island）。每个系统内多数礁体均设置重复采样点，样本采集时间分别为：2004年1月斯科特礁系统礁坡、2005年4月罗利沙洲礁坡、2006年9月布鲁尔岛礁坡。盔形梳状珊瑚的数据集包含从斯科特礁采样的287株个体的基因型数据（详细信息参见另一项元数据记录）。除布鲁尔岛的2个采样点外，其余所有采样点均记录了采样珊瑚株相对于300米样带的精确位置，以及每条样带起点的GPS坐标。盔形梳状珊瑚共有8对采自同一采样点的个体基因型完全一致，细枝鹿角珊瑚则为7对。每对中仅保留1株个体用于后续分析，最终每个采样点的分析样本量为21至50株。已记录的微卫星标记信息包括：每个位点和采样点的等位基因数（A）、观测杂合度（HO）与期望杂合度（HE）占比，以及每个位点和采样点的FIS值（FIS All loci）。同时计算了各项统计量的平均值：包括所有位点的等位基因数（A All loci）、每个采样点所有位点的期望杂合度（He All loci）、所有采样点的整体期望杂合度（He All sites）；以及每个采样点的私有等位基因数（Pva）、总等位基因数（Atotal），以及所有采样点每位点的平均等位基因数（Amean）。位点命名规则为：以物种名前缀开头，后接2、3、4或5，分别对应二核苷酸、三核苷酸、四核苷酸或五核苷酸重复基序类型，最后接编号：盔形梳状珊瑚的位点包括Sh2-002、Sh2-006、Sh3-003、Sh3-004、Sh3-007、Sh3-008、Sh3-009、Sh4-001；细枝鹿角珊瑚的位点包括Amil2-006、Amil2-010、Amil2-011、Amil2-012、Amil2-018、Amil2-022、Amil5-028。与基于生活史的预期一致，育幼型珊瑚的种群遗传分化水平显著高于广播产卵型珊瑚。此外，两个物种种群在礁体系统间（间距>100km）、礁体间（间距>10km）以及礁体内均存在显著遗传分化。为进一步解析种群隔离程度、有效种群大小，以及无性繁殖与有性繁殖的相对重要性，本研究检验了高纬度远岸礁体与低纬度近岸礁体之间的遗传多样性与克隆基因型多样性差异。