Ref ID : 4078
Gunther Steinbruck and Martin Schlegel; Characterization of Two Sibling Species of the Genus Stylonychia (Ciliata, Hypotricha): S. mytilus Ehrenberg, 1838 and S. lemnae n. sp. II. Biochemical Characterization. J.Protozool. 30(2):294-300, 1983
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The two closely related hypotrichous ciliate species, Stylonychia lemnae and S. mytilus, have been compared with respect to their isoenzyme patterns, their macronuclear DNA banding patterns, and micronuclear DNA banding patterns after restriction enzyme digestion. Since macronuclear DNA contains mainly protein-coding sequences and since the micronuclear DNA patterns represent mainly the repetitive fraction of the genome, these results, together with the isoenzyme patterns, reflect differences on three different levels of molecular evolution between morphologically very similar species. Each of the three methods allows an unequivocal identification of each of the two species. Intraspecific variation seems to be greatest among the repetitive sequences of the micronuclear genomes. By using the isoenzyme data and the formula of Nei (19) the genetic distance between the two species is calculated and compared with the results from other protozoa and different Drosophila species. Despite their morphological similarity, the two species show a considerable amount of evolutionary divergence on the three molecular levels which have been investigated.