کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
4749436 1360443 2006 12 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Phylogenetic affinities of an enigmatic nannoplankton, Braarudosphaera bigelowii based on the SSU rDNA sequences
موضوعات مرتبط
مهندسی و علوم پایه علوم زمین و سیارات فسیل شناسی
پیش نمایش صفحه اول مقاله
Phylogenetic affinities of an enigmatic nannoplankton, Braarudosphaera bigelowii based on the SSU rDNA sequences
چکیده انگلیسی

The phylogenetic position of an enigmatic calcareous nannoplankton Braarudosphaera bigelowii, whose taxonomic position has long been questioned, was investigated using molecular genetic methods. The SSU rDNA sequences of B. bigelowii were obtained using a single cell PCR technique independently from two single cells isolated from field samples. A BLAST search revealed that the SSU rDNA of B. bigelowii was most similar to those of the division Haptophyta. Subsequent phylogenetic analyses showed that B. bigelowii was included in a clade comprising members of the orders Isochrysidales and Coccolithales, the genus Chrysoculter and two unidentified haptophytes. Morphometric measurements of extant B. bigelowii populations were made to obtain precise information on their intraspecific size variation. The results showed that these populations could be subdivided into a small form (< 2.4 μm), an intermediate form A (4.0–5.3 μm), and an intermediate form B (5.3–7.2 μm), although the borders of the latter two forms overlapped. The SSU rDNA sequences showed the presence of 10-bp substitutions plus six insertions/deletions between specimens of intermediate forms A and B. The levels of DNA variation between them suggested that these two forms are genetically distinct from each other.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Marine Micropaleontology - Volume 60, Issue 2, 20 July 2006, Pages 145–156
نویسندگان
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