Reports

Evidence from 18S ribosomal RNA sequences that lampreys and hagfishes form a natural group

Science  07 Aug 1992:
Vol. 257, Issue 5071, pp. 787-789
DOI: 10.1126/science.1496398

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Abstract

Lampreys and hagfishes (cyclostomes) traditionally were considered to be a natural (monophyletic) group. Recently, the consensus of opinion, based largely on morphological analyses, has shifted to a view that lampreys are more closely related to jawed vertebrates (gnathostomes) than to hagfishes. Phylogenetic comparisons of 18S ribosomal RNA sequences from two hagfishes, two lampreys, a tunicate, a lancelet, and a number of gnathostomes support the monophyly of the cyclostomes. These data force a reassessment of several features of early vertebrate evolution.