The phylogeny of lampreys is controversial, because they possess few taxon-distinctive morphological characters. This is especially true of the relationships among the genus Lethenteron and the closely related genera Eudontomyzon and Lampetra. Thus, the first objective of this thesis was to use DNA sequences of the mitochondrial cytochrome b gene and two nuclear gene introns to infer the phylogeny among these three genera. I found that: 1) Lethenteron plus Eudontomyzon morii without Lethenteron ninae, Lethenteron zanandreai, and Lethenteron sp. S (a distinct cryptic species in the Lethenteron reissneri complex) was monophyletic; 2) Lampetra from the Pacific drainage of North America and Lampetra aepyptera should each be separated, as distinct genera, from Lampetra (including Lethenteron ninae and Lethenteron zanandreai) from the Atlantic drainage of Eurasia; and 3) the remaining Eudontomyzon and the Atlantic Lampetra clustered together in all analyses. The second objective of this thesis was to resolve the relationship among closely related Lethenteron species. Lampreys are either parasitic or non-parasitic, and each non-parasitic (satellite) species is believed to have been derived independently from the parasitic (stem) ancestor. In the phylogenetic analysis, the parasitic Arctic lamprey Lethenteron camtschaticum and its four satellite species were not reciprocally monophyletic. Since network methods are generally more useful for closely related haplotypes than bifurcating trees, a haplotype network of these five Lethenteron species was generated using the cytochrome b gene sequences; Lethenteron appendix showed haplotype frequency distribution differences but there was little support for recognizing the other four taxa as distinct species.
| Identifer | oai:union.ndltd.org:MANITOBA/oai:mspace.lib.umanitoba.ca:1993/23657 |
| Date | 25 June 2014 |
| Creators | Li, Youyang |
| Contributors | Docker, Margaret (Biological Sciences), Sharanowski, Barb (Entomology) Marcus, Jeffrey (Biolgical Sciences) |
| Source Sets | University of Manitoba Canada |
| Detected Language | English |
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