Spawning times, reproductive compatibilities and genetic structuring in the Acropora aspera group:: evidence for natural hybridization and semi-permeable species boundaries in corals
Spawning times, reproductive compatibilities and genetic structuring in the Acropora aspera group:: evidence for natural hybridization and semi-permeable species boundaries in corals
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DOI：
10.1046/j.1365-294x.2002.01527.x
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发表时间：
2002-08-01
影响因子：
4.9
通讯作者：
Miller, DJ
中科院分区：
文献类型：
--
作者：
Van Oppen, MJH;Willis, BL;Miller, DJ
通过离体繁殖试验、产卵时间比较、核糖体DNA内转录间隔区（rDNA ITS）和5.8S区序列分析，研究了印度-太平洋鹿角珊瑚组（Acroporaspera group）5种同域分布珊瑚的种间界限。育种试验表明，至少在所有测试的物种对的一些菌落之间存在生殖相容性，这表明自然杂交和渐渗的巨大潜力。鹿角珊瑚ITS区具有极高的变异性（ITS 1的相似性高达62%，5.8S的相似性为11%，ITS 2的相似性为43%），但大部分变异在5个种中的4个种之间共享，A.千孔藻A. papillare、刺萼草A. pulchra和A. spathulata，符合广泛的渗入。系统发育分析并没有解决这四个物种作为不同的集群在一个广泛的地理区域从大堡礁南部到巴布亚新几内亚。而第5种A.在系统发育分析中，aspera是一个独立的分支。这是一致的，我们观察到的半渗透性的时间障碍，涉及这和其他四个物种之间的产卵时间的差异。虽然所有五个物种的大多数殖民地一般在90分钟内产卵，在四年中有两年，配子缺席之前，至少有一些A。阿斯培拉殖民地。因此，我们的数据表明，短暂的生殖障碍可能是一年到一年的产卵日期的变化的结果，这种差异的产卵时间有助于在这组中的鹿角珊瑚物种之间检测到的遗传结构。通过A的观察证实了通过生殖屏障的偶尔泄漏。[医]糙叶草pulchra F-1杂种，根据ITS序列的加和性鉴定。
Species boundaries among five sympatric coral species of the Indo-Pacific Acropora aspera group were examined by a combination of in vitro breeding trials, comparisons of spawning times and DNA sequence analysis of ribosomal DNA internal transcribed spacer (rDNA ITS) and 5.8S regions. The breeding trials showed that reproductive compatibility exists between at least some colonies of all the species pairs tested, suggesting a large potential for natural hybridization and introgression. The Acropora ITS regions exhibited extremely high levels of variability (up to similar to62% for ITS1, similar to11% for 5.8S and similar to43% for ITS2), but most of the variation was shared among four of the five species, A. millepora , A. papillare , A. pulchra and A. spathulata, consistent with extensive introgression. Phylogenetic analyses did not resolve these four species as distinct clusters across a wide biogeographic region stretching from the southern Great Barrier Reef to Papua New Guinea. However, most colonies of the fifth species, A. aspera , constituted a distinct clade in phylogenetic analyses. This is consistent with our observations of a semi-permeable temporal barrier involving differences in spawning times between this and the other four species. Although the majority of colonies of all five species generally spawned within 90 min of each other, in two out of four years, gametes were absent prior to mass spawning episodes from at least some A. aspera colonies. Hence, our data suggest that transient reproductive barriers may be the result of year-to-year variation in the date of spawning and that this difference in spawning time contributes to the genetic structure detected among Acropora species in this group. Occasional leakage through the reproductive barrier was confirmed by the observation of A. aspera xA. pulchra F-1 hybrids, identified based on additivity of ITS sequences.