Get access

Hybridization and introgression between Callicarpa japonica and C. mollis (Verbenaceae) in central Japan, as inferred from nuclear and chloroplast DNA sequences

Authors

  • Hirokazu Tsukaya,

    Corresponding author
    1. National Institute for Basic Biology/Center for Integrated Bioscience, Myodaiji-cho, Okazaki 444–8585, Japan,
    2. School of Advanced Sciences, The Graduate University for Advanced Studies, Shonan Village, Hayama, Kanagawa 240–0193, Japan
    Search for more papers by this author
  • Tatsuya Fukuda,

    1. Department of Ecology and Evolutionary Biology, Graduate School of Life Sciences, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980–8578, Japan,
    Search for more papers by this author
  • Jun Yokoyama

    1. Department of Ecology and Evolutionary Biology, Graduate School of Life Sciences, Tohoku University, Aoba, Aramaki, Aoba-ku, Sendai, Miyagi 980–8578, Japan,
    Search for more papers by this author

Hirokazu Tsukaya. Fax: + 81 564 55 7512; E-mail: tsukaya@nibb.ac.jp

Abstract

Callicarpa × shirasawana is a natural hybrid between C. japonica and C. mollis, and has a morphology that is intermediate between those of the parent species. Characterization of natural Callicarpa populations in the Atsumi Peninsula of central Japan, which all three of the above species inhabit sympatrically, revealed hybrids with various morphologies. Molecular analysis revealed a high occurrence of introgression of the C. japonica genome into that of C. mollis. Moreover, all individuals examined with morphology similar to that of C. mollis had genetic traces of hybridization with C. japonica. Molecular analysis of individual C. mollis and C. japonica from five other areas of Japan showed that introgression of C. japonica into C. mollis occurs widely. Molecular data also strongly suggested that the previously recognized C. × shirasawana individuals with intermediate morphology are not F1 hybrids between C. japonica and C. mollis, but instead are progeny of C. × shirasawana backcrossed with C. japonica. Moreover, it was revealed that individuals with F1-type genotypes are indistinguishable morphologically from pure C. mollis. The results of the present study point to the need for re-evaluation of natural populations of C. mollis and C. × shirasawana.

Ancillary