Pseudo-cryptic speciation in Braarudosphaera bigelowii (Gran and Braarud) Deflandre
Pseudo-cryptic speciation in Braarudosphaera bigelowii (Gran and Braarud) Deflandre
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DOI：
10.1016/j.marmicro.2009.06.001
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发表时间：
2009-09-01
影响因子：
1.9
通讯作者：
Horiguchi, Takeo
中科院分区：
文献类型：
--
作者：
Hagino, Kyoko;Takano, Yoshihito;Horiguchi, Takeo
从日本周边海域的13个自然采集细胞中获得了部分SSU rDNA序列。结合已报道的两个序列，将15个样本分为5个SSU rDNA基因型I-V。根据形成球球的五柱石的边长，这些标本也被分为三种大小-形态类型：中间型-A、中间型-B和大型型。大斑潜蝇的基因分型与体型有很好的相关性，但与采样面积无相关性。这一结果表明，Bigelovvii的大小差异是物种形成的结果，而不是种群内变异的结果。因此，基因I和II(中间型-A)和基因IV和V(大型)被认为是典型的比格罗氏杆菌(基因III，中间型-B)的假隐亲种，这与最初对该物种的描述相一致。从SSU rDNA序列中可以看出，基因V型来源于基因IV型，基因IV型来源于基因III型。基因III型-V型标本的五倍体大小与其分枝顺序一致。本研究中观察到的活体大小复合体的大小-形态关系的一致性表明，古生物学研究报告的不同地质时代的大小范围的不一致源于地质历史中‘大小-形态复合体’谱系中额外的伪隐形物种形成。(C)2009爱思唯尔B.V.保留所有权利。
Partial SSU rDNA sequences were obtained from 13 naturally collected cells of Braarudosphaera bigelowii obtained from various parts of seas surrounding Japan. Together with the two previously reported sequences, 15 specimens were classified into five SSU rDNA Genotypes I-V. Based on the side length of the pentaliths forming the coccosphere, these specimens were also classified into three size-morphotypes: Intermediate form-A, Intermediate form-B, and Large form. Genotypes of B. bigelowii were well correlated with size-morphotypes but not with sampling area. This result indicates that size differences in B. bigelovvii are the results of speciation and not of intra-population variety. Therefore, Genotypes I and II (Intermediate form-A) and Genotypes IV and V (Large form) are regarded as pseudo-cryptic sibling species of typical B. bigelowii (Genotype III, Intermediate form-B), which corresponds to the original description of the species. From the SSU rDNA sequences, it is evident that Genotype V arose from Genotype IV, and Genotype IV originated from Genotype III. The specimens of Genotypes III-V showed size increase of pentaliths in accordance with their branching order. The consistency in the relationship between genotypes and size-morphotypes of living B. bigelowii-complex observed in this study suggests that inconsistency of size range of 'B. bigelowii pentaliths among different geological ages reported by palaeontological studies stems from additional pseudo-cryptic speciation in the lineage of 'B. bigelowii' in the geological past. (C) 2009 Elsevier B.V. All rights reserved.