Environmental Biology of Fishes

, Volume 48, Issue 1–4, pp 127–155

Phylogeny of the Acipenseriformes: cytogenetic and molecular approaches

  • Vadim J. Birstein
  • Robert Hanner
  • Rob DeSalle
Article

Abstract

The review of the data on karyology and DNA content in Acipenseriformes shows that both extant families, the Polyodontidae and Acipenseridae, originated from a tetraploid ancestor which probably had a karyotype consisting of 120 macro- and microchromosomes and DNA content of about 3.2–3.8 pg per nucleus. The tetraploidization of the presumed 60-chromosome ancestor seems to have occurred at an early time of evolution of the group. The divergence of the Acipenseridae into Scaphirhyninae and Acipenserinae occurred without polyploidization. Within the genus Acipenser, polyploidization was one of the main genetic mechanisms of speciation by which 8n and 16n-ploid species were formed. Individual gene trees constructed for sequenced partial fragments of the 18S rRNA (230 base pairs, bp), 12S rRNA (185 bp), 16S rRNA (316 bp), and cytochrome b (270 bp) genes of two Eurasian (A. baerii and A. ruthenus) and two American (A. transmontanus and A. medirostris) species of Acipenser, Huso dauricus, Pseudoscaphirhynchus kaufmanni, Scaphirhynchus albus, and Polyodon spathula showed a low level of resolution; the analysis of a combined set of data for the four genes, however, gave better resolution. Our phylogeny based on molecular analysis had two major departures from existing morphological hypotheses: Huso dauricus is a sister-species to Acipenser instead of being basal to all acipenseriforms, and Scaphirhynchus and Pseudoscaphirhynchus do not form a monophyletic group. The phylogenetic tree constructed for the cytochrome b gene fragments (with inclusion of 7 additional species of Acipenser) supported the conclusion that octoploid species appeared at least three times within Acipenser.

sturgeon paddlefish Huso Acipenser Scaphirhynchus Pseudoscaphirhynchus Polyodon Psephurus karyotype chromosome macrochromosome microchromosome genome DNA content 18S rRNA gene cytochrome 12S mtrRNA gene 16s mtrRNA gene rate of molecular evolution phylogeny evolution 

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Copyright information

© Kluwer Academic Publishers 1997

Authors and Affiliations

  • Vadim J. Birstein
    • 1
  • Robert Hanner
    • 2
  • Rob DeSalle
    • 3
  1. 1.The Sturgeon SocietyNew YorkU.S.A
  2. 2.Department of BiologyUniversity of OregonEugeneU.S.A
  3. 3.Department of EntomologyAmerican Museum of Natural HistoryNew YorkU.S.A

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