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Journal of Molecular Evolution

, Volume 50, Issue 5, pp 456–464 | Cite as

The Vertebrate 7S K RNA Separates Hagfish (Myxine glutinosa) and Lamprey (Lampetra fluviatilis)

  • Halil-Cem  Gürsoy
  • Dorota  Koper
  • Bernd-Joachim  Benecke

Abstract.

7S RNA sequences from the hagfish (Myxiniformes) and lamprey (Petromyzontiformes) were cloned and analyzed. In both species, 7S L RNA (also designated SRP RNA, since it represents the RNA constituent of the signal recognition particle) was clearly detectable. The sequence similarity between the two species was 86%, compared with about 75% similarity between either of these species and mammals. 7S K RNA was also cloned from the lamprey. The similarity between the 7S K RNA of the lamprey and that of mammals was 68%. Interestingly, several interspersed elements were found with nearly 100% similarity compared with mammals. In contrast to the lamprey, no 7S K RNA-related sequences were detectable among hagfish RNA, neither in northern blots nor with the PCR assay. In view of the significant conservation between the 7S K RNA of lamprey and that of mammals (human), this unexpected result clearly separates lamprey and hagfish. In addition, the lack of detectable 7S K RNA sequences in an outgroup, such as amphioxus, indicates that these results do not reflect an autapomorphy of hagfish. Therefore, our data provide additional support to the notion of a sister group relationship between Petromyzontiformes and gnathostomous vertebrates to the exclusion of Myxiniformes.

Key words: 7S RNA — Small nuclear RNA — Vertebrate evolution — Cyclostomata — Gnathostomata 

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Copyright information

© Springer-Verlag New York Inc. 2000

Authors and Affiliations

  • Halil-Cem  Gürsoy
    • 1
  • Dorota  Koper
    • 1
  • Bernd-Joachim  Benecke
    • 1
  1. 1.Department of Biochemistry, Faculty of Chemistry, Ruhr-University, D-44780 Bochum, GermanyDE

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