Planktic foraminiferal molecular evolution and their polyphyletic origins from benthic taxa
Planktic foraminiferal molecular evolution and their polyphyletic origins from benthic taxa
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DOI：
10.1016/s0377-8398(96)00057-6
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发表时间：
1997-04-01
影响因子：
1.9
通讯作者：
Brown, AJL
中科院分区：
文献类型：
--
作者：
Darling, KF;Wade, CM;Brown, AJL
基于小亚基 (SSU) 核糖体 (r) RNA 基因部分序列的系统发育分析表明，浮游和底栖有孔虫在真核生物内形成独特的单系群。为了确定底栖和浮游有孔虫之间的进化关系，有刺和无刺浮游生物属的代表已被置于分子 SSU rDNA 系统发育中，该系统发育包含迄今为止可用的底栖亚目序列。我们的系统发育分析表明，浮游有孔虫起源于多系，并非仅从中侏罗世的单一“globigerinid-like”谱系进化而来，而是源自至少两个祖先的底栖系。Neogloboquadrina dutertrei的底栖祖先可能晚于中侏罗世进入浮游生物，对相关现存物种的进一步调查应能提供这一时间的指示。事件。无刺物种 Globorotalia menardii 的进化起源仍不清楚。浮游棘物种的分歧总体上支持基于化石记录的近期系统发育，该系统发育推断出来自渐新世中晚期的globigerinid共同祖先的辐射。分支模式表明，主要的刺分支内可能存在四个不同的群体，在它们之间观察到很大的进化距离。 Globigerinoides conglobatus 与 Globigerinoides ruber 强烈聚集，并且与 Globigerinella siphonifera、Orbulina universa 和 Globigerinoides sacculifer 不同。SSU rRNA 基因的保守区域显示出足够的变异，可以在物种水平上区分有孔虫。在粉红色和白色形式的 Gs、块茎和 Ge 之间观察到巨大的遗传差异。管虫 I 型和 II 型。 Ge的两种类型。传统的古生物学方法无法区分管虫，这对于追踪化石谱系和根据化石记录估计分子进化速率具有相当大的意义。保守区域在物种内表现出高度的序列同一性，为物种鉴定提供了特征序列。尽管在从加勒比海和西太平洋收集的标本中，在 G. sacculifer 和 O. universa 中观察到了完整的序列同一性，但该基因的可变区可能为某些物种的种群水平研究提供了信息。
Phylogenetic analyses based on partial sequences of the small subunit (SSU) ribosomal (r) RNA gene have shown that the planktic and benthic foraminifera form a distinct monophyletic group within the eukaryotes. In order to determine the evolutionary relationships between benthic and planktic foraminifers, representatives of spinose and non-spinose planktic genera have been placed within a molecular SSU rDNA phylogeny containing sequences of the benthic suborders available to date. Our phylogenetic analysis shows that the planktic foraminifers are polyphyletic in origin, not evolving solely from a single 'globigerinid-like' lineage in the Mid-Jurassic, but derived from at least two ancestral benthic lines, The benthic ancestor of Neogloboquadrina dutertrei may have entered the plankton later than the Mid-Jurassic, and further investigation of related extant species should provide an indication of the timing of this event. The evolutionary origin of the non-spinose species Globorotalia menardii remains unclear. The divergences of the planktic spinose species generally support recent phylogenies based on the fossil record, which infer a radiation from a globigerinid common ancestor in the Mid- to Late Oligocene. The branching pattern indicates that there are possibly four distinct groups within the main spinose clade, with large evolutionary distances being observed between them. Globigerinoides conglobatus clusters strongly with Globigerinoides ruber and are divergent from Globigerinella siphonifera, Orbulina universa and Globigerinoides sacculifer.Conserved regions of the SSU rRNA gene show sufficient variation to discriminate foraminifers at the species level, Large genetic differences have been observed between the pink and white forms of Gs, tuber and between Ge. siphonifera Type I and II. The two types of Ge. siphonifera cannot be discriminated by traditional palaeontological methods, which has considerable implications for tracing fossil lineages and for the estimation of molecular evolutionary rates based upon the fossil record. The conserved regions show a high degree of sequence identity within a species, providing signature sequences for species identification. The variable regions of the gene may prove informative for population level studies in some species although complete sequence identity was observed in G. sacculifer and O. universa between specimens collected from the Caribbean and Western Pacific.