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Insights into the Evolution of Nuclear Dualism in the Ciliates Revealed by Phylogenetic Analysis of rRNA Sequences
Author(s) -
HAMMERSCHMIDT BRIGITTE,
SCHLEGEL MARTIN,
LYNN DENIS H.,
LEIPE DETLEF D.,
SOGIN MITCHELL L.,
RAIKOV IGOR B.
Publication year - 1996
Publication title -
journal of eukaryotic microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.067
H-Index - 77
eISSN - 1550-7408
pISSN - 1066-5234
DOI - 10.1111/j.1550-7408.1996.tb01396.x
Subject(s) - biology , phylogenetic tree , monophyly , lineage (genetic) , evolutionary biology , maximum parsimony , phylogenetics , zoology , paraphyly , phylum , clade , genetics , gene
The small subunit rRNA gene sequences of the karyorelictean ciliates, Loxodes striatus and Protocruzia sp., and the heterotrichian ciliates, Climacostomum virens and Eufolliculina uhligi , were used to test the evolution of nuclear dualism in the Phylum Ciliophora. Phylogenies derived using a least squares distance method, neighbour joining, and maximum parsimony demonstrate that the karyorelictean ciliates sensu Small and Lynn, 1985 do not form a monophyletic group. However, Loxodes and the heterotrich ciliates form the first branch in the ciliate lineage, and Protocruzia branches, in distance methods, basal to the spirotrich lineage. It is proposed that Protocruzia be removed from the Class Karyorelictea, and placed in closer taxonomic association with the spirotrich lineage. The distribution of nuclear division types along the phylogenetic tree is consistent with the notion that macronuclei incapable of division represent a derived rather than a primitive or “karyorelictid” character trait.