1. Contrasting patterns of DNA variation in natural populations of two related conifers, Cryptomeria japonica and Taxodium distichum (Cupressaceae sensu lato)
- Author
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Yutaka Ushio, Tomoyuki Kado, Yoshihiko Tsumura, Hidenori Tachida, and Hiroshi Yoshimaru
- Subjects
Cupressaceae ,Genetic Speciation ,Cryptomeria ,Molecular Sequence Data ,Population ,Amidophosphoribosyltransferase ,Taxodium ,Biology ,Genes, Plant ,Japonica ,Nucleotide diversity ,Evolution, Molecular ,Gymnosperm ,Sequence Homology, Nucleic Acid ,Botany ,Genetics ,Intramolecular Lyases ,education ,Molecular Biology ,education.field_of_study ,Polymorphism, Genetic ,Base Sequence ,Genetic Variation ,General Medicine ,Plant Components, Aerial ,biology.organism_classification ,Aldehyde Oxidoreductases ,Ferredoxins ,Selective sweep - Abstract
We investigated DNA variation within and between two closely related conifers, Cryptomeria japonica and Taxodium distichum, at nuclear loci encoding ferredoxin, glutamyl-tRNA reductase, lycopene beta cyclase, and phosphoribosylanthranilate transferase. Average nucleotide diversity at silent sites was estimated to be 0.0035 (SE 0.0012) in C. japonica and 0.0058 (SE 0.0006) in T. distichum. One population in C. japonica was differentiated from the others but generally there was not much differentiation among populations or varieties within the two species. However, the two species seemed to differ in frequency spectra of DNA polymorphisms. Excesses of intermediate-frequency variants were found in C. japonica, whereas excesses of both rare and high-frequency variants were found in T. distichum, which suggested different histories of population structures in the two species. Deviations from the standard neutral expectations in DNA polymorphisms were found by applications of neutrality tests. The results show that actions of selection to respective loci seem to differ between the two species, indicating differences of interaction among evolutionary factors.
- Published
- 2006
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