Hierarchical analysis of population genetic variation in mitochondrial and nuclear genes of Daphnia pulex

T. J. Crease, M. Lynch, K. Spitze

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62 Scopus citations

Abstract

The geographic structure of Daphnia pulex populations from the central United States is analyzed with respect to isozyme and mitochondrial DNA variation. The species complex consists of cyclic and obligate parthenogens. A hierarchical analysis of population structure in the cyclic parthenogens by using a fixation-index approach indicates that this is one of the most extremely subdivided species yet studied. This genetic structure, much of which accrues within 100 km, is certainly due in part to the limited dispersal ability of Daphnia. However, previous work has shown that fluctuating selection can account for the spatial heterogeneity in isozyme frequencies in these populations. This may explain why the population subdivision for the mitochondrial genome increases approximately three times as rapidly with distance as does that for nuclear genes, which is slower than the neutral expectation. The obligate parthenogens are shown to be polyphyletic in origin, evolutionarily young, and, in some cases, geographically widespread.

Original languageEnglish (US)
Pages (from-to)444-458
Number of pages15
JournalMolecular biology and evolution
Volume7
Issue number5
StatePublished - Oct 2 1990
Externally publishedYes

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Keywords

  • Daphnia
  • geographic variation
  • isozymes
  • mitochondrial DNA
  • population structure

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Molecular Biology
  • Genetics

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