TITLE: The mitochondrial DNA molecule of the hagfish (Myxine glutinosa) and vertebrate phylogeny. AUTHOR: Rasmussen, Ann-Sofie; Janke, Axel; Arnason, Ulfur. AUTHOR AFFIL: Div. Evolutionary Molecular Systematics, Dep. Genetics, Univ. Lund, Solvegatan 29, S-223 62 Lund, Sweden. SOURCE TITLE: Journal of Molecular Evolution 46, no. 4 (April, 1998): 382-388. ABSTRACT: The vertebrates are traditionally classified into two distinct groups, Agnatha (jawless vertebrates) and Gnathostomata (jawed vertebrates). Extant agnathans are represented by hagfishes (Myxiniformes) and lampreys (Petromyzontiformes), frequently -grouped together within the Cyclostomata. Whereas the recognition of the Gnathostomata as a clade is commonly acknowledged, a consensus has not been reached regarding whether or not Cyclostomata represents a clade. In the present study we have used newly established sequences of the protein-coding genes of the mitochondrial DNA molecule of the hagfish to explore agnathan and gnathostome relationships. The phylogenetic analysis of Pisces, using echinoderms as outgroup, placed the hagfish as a sister group of Vertebrata sensu stricto, i.e., the lamprey and the gnathostomes. The phylogenetic analysis of the Gnathostomata identified a basal divergence between gnathostome fishes and a branch leading to birds and mammals, i.e., between "Anamnia" and Amniota. The lungfish has a basal position among gnathostome fishes with the teleosts as the most recently evolving lineage. The findings portray a hitherto unrecognized polarity in the evolution of bony fishes. The presently established relationships are incompatible with previous molecular studies.Back to home page.