Geographic differences in species boundaries among members of the Montastraea annularis complex based on molecular and morphological markers
Geographic differences in species boundaries among members of the Montastraea annularis complex based on molecular and morphological markers
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DOI：
10.1111/j.0014-3820.2004.tb01648.x
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发表时间：
2004-02-01
期刊：
影响因子：
3.3
通讯作者：
Knowlton, N
中科院分区：
文献类型：
--
作者：
Fukami, H;Budd, AF;Knowlton, N
Montastraea annularis复合体（M. annularis，M. franksi和M. faveolata）是西大西洋主要的造礁者，其物种地位已经有十多年的争议。虽然在菌落形态和生殖特性存在差异，种间受精是可能的，在实验室和遗传分化是轻微的。在这里，我们比较了三个类群的遗传和形态在巴拿马和巴哈马群岛，广泛分离的位置跨越其大部分的地理范围。在巴拿马，三个AFLP位点，线粒体基因组的非编码区，和ITS序列的分析表明，M。faveolata在遗传上是高度分化的。判别函数分析也表明，没有重叠与其他两个物种的珊瑚，包括殖民地的精细结构。种间杂交幼虫的遗传分析。faveolata和其他两个分类群证实了幼虫的杂交状态，但在田间没有观察到最可能的F 1基因型的例子。虽然M. annularis和M. franksi的相似性更高，但它们在两个AFLP位点和线粒体非编码区也表现出很强的频率差异，以及不同的珊瑚石结构。相反，在巴哈马群岛，这三个类群表现出重叠的形态。Montastraea franksi和M. annularis在遗传上是不可区分的，M. faveolata在较少的遗传位点上存在差异。然而，再一次，最可能的F基因型涉及M。未观察到蜂窝状。巴拿马和巴哈马之间的地理差异解释了为什么过去的研究对这三个物种的状况得出了不同的结论。一般来说，遗传和形态学数据表明，北向南杂交梯度，在北方渗入最强的证据。然而，生殖数据显示没有这种趋势，在北方，基因流动的内在障碍相当或更强。
The three members of the Montastraea annularis complex (M. annularis, M. franksi, and M. faveolata) are dominant reef builders in the western Atlantic whose species status has been controversial for over a decade. Although differences in colony morphology and reproductive characteristics exist, interspecific fertilizations are possible in the laboratory and genetic differentiation is slight. Here we compare the three taxa genetically and morphologically in Panama and the Bahamas, widely separated locations spanning most of their geographic ranges. In Panama, analyses of three AFLP loci, a noncoding region of the mitochondrial genome, and ITS sequences reveal that M. faveolata is strongly differentiated genetically. Discriminant function analysis also indicates no overlap with the other two species in the fine structure of the corallites that comprise the colony. Genetic analyses of larvae from interspecific crosses between M. faveolata and the other two taxa confirmed the hybrid status of the larvae, but no examples of the most probable F, genotype were observed in the field. Although M. annularis and M. franksi were more similar, they also exhibited strong frequency differences at two AFLP loci and in the mitochondrial noncoding region, as well as distinct corallite structure. In the Bahamas, in contrast, the three taxa exhibited overlapping morphologies. Montastraea franksi and M. annularis were indistinguishable genetically, and M. faveolata was distinct at fewer genetic loci. Once again, however, the most probable F, genotype involving M. faveolata was not observed. Geographic differences between Panama and the Bahamas explain why past studies have come to different conclusions concerning the status of the three species. In general, the genetic and morphological data suggest a north to south hybridization gradient, with evidence for introgression strongest in the north. However, reproductive data show no such trend, with intrinsic barriers to gene flow comparable or stronger in the north.