The meiotic process of the zygotes from two Corbicula species in Tone River [Japan]
2006
Ishibashi, R.(Kinki Univ., Shirahama, Wakayama (Japan). Fisheries Lab.) | Kumamoto, A. | Kato, T. | Nemoto, T. | Komaru, A.
The processes of meiosis and fertilization in exotic species Corbicula fluminea and C. papyracea collected at Tone River were compared with that of domestic C. japonica. Microfluorometric analyses revealed that C. fluminea included diploids and triploids and both produced non-reductional sperm. The eggs from C. fluminea showed androgenetic process. They extruded all maternal chromosomes at first meiosis as two first polar bodies. On the contrary, C. papyracea and C. japonica were diploids and produced haploid sperm. In both species the eggs showed normal process of meiosis and fertilization (i.e. formation of first and second polar bodies and female pronucleus). The eggs from C, japonica inseminated by sperms from C, papyracea showed normal development up to D-shaped veliger larvae. This result suggests that hybridization of both species may occur at Tone River.
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