Evaluation of the meaning of foraminiferal test morphology based on DNA sequences

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To evaluate the meaning of benthic foraminiferal test morphology, molecular phylogenetic analyzes have carried out for several selected genera. Glabratella and Bolivina and related genera were selected for analysis, because these genera have been well documented morphologically. Both DNA extractions and PCR techniques were mostly adopted from Pawlowski et al. (1995). We analyzed about 650 nucleotic acid base pairs from LSU ribosomal DNA.Specific primers for foraminifera were used for each PCR step. Amplified DNA fragments were cloned at plasmid vectors, then sequenced with an automatic sequencer.DNA sequences of forminifera show several interesting results. Genetic variation within local populations of Glabratella is lower than in Bolivina and Ammonia. This may reflect differences in mode of reproduction among foraminiferal genera. Molecular phylogenies calculated from nucleotide sequencing data had different cluster groups than a phylogeny based on morphological data. Calculations of the molecular phylogenetic trees were made with both parsimony and neighbor joining methods. Cluster groups of molecular data were, however, well related to morphological cluster groups that are based on functional morphology. For instance, radial grooves around the aperture area, which may be related to reproductive behavior, is similar among taxa grouped by molecular clustering. In Glabratella opercularis the variation within one of the populations was greater than that fpund within other entire species that we have studied. Whithin this population morphological variation is typical for foraminiferal populations and it is not possible to subdivide the population based on morphological characters. These results suggest that reevaluation of foraminiferal test morphology from the view point of functional morphology may enable creation of phylogenies based on morphology that are cnoformable with molecular phylogenies.