Artificially Produced Chimeras between Haploids and Diploids in Japanese Anurans
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An investigation was undertaken to test the validity of the hypothesis that edema is the major cause of the low viability of haploid embryos and tadpoles. Chimeras were produced by exchanging the anterior and posterior parts of haploid embryos (H) with those of diploid embryos (D) by joining them after cutting transversely at the site immediately before and behind the pronephros (p). It was found that severe edema usually found in haploid embryos at the early stage is remarkably diminished in the Dp・H and H・pD chimeras which have diploid pronephroi in the anterior and posterior diploid halves, respectively. Especially, the Dp・H chimeras which consist of anterior diploid halves with pronephroi and posterior haploid halves are comparatively good in development. Of the Dp・H chimeras, 18 (9.7%) in Rana nigromaculata and 15 (10%) in Rana japonica attained the stage immediately before or after the completion of metamorphosis.
Scientific report of the Laboratory for Amphibian Biology
Institute for Amphibian Biology, Hiroshima University