Recovery of viability in triploid hybrids between Japanese and European water frogs, and their reproductive capacity.
Diploid and triploid hybrids, consisting of the various combinations of chromosome set and cytoplasm between Rana nigromaculata and Rana lessonae, were generated in order to study their viability and reproductive capacity. Reciprocal diploid hybrids and allotriploids, which had two lessonae genomes and one nigromaculata genome in nigromaculata cytoplasm, all died without closing their neural folds. Allotriploids, which had two nigromaculata genomes and one lessonae genome in nigromaculata cytoplasm, all grew into healthy mature males in 12.4% (21 frogs) of zygotes. Following the elimination of lessonae chromosomes, ten of these males produced many spermatozoa containing a haploid set of nigromaculata chromosomes. Other allotriploids, which had either one nigromaculata genome and two lessonae genomes or two nigromaculata genomes and one lessonae genome in lessonae cytoplasm, exhibited slightly improved viability.
Laboratory for Amphibian Biology, Faculty of Science, Hiroshima University, Japan.
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Ohtani
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Kondo
D000818:Animals; D005260:Female; D006824:Hybridization, Genetic / Q000235:genetics; D008297:Male; D011003:Ploidies; D011898:Ranidae / Q000235:genetics / Q000502:physiology*; D012098:Reproduction; D015996:Survival Rate; D013737:Testis / Q000033:anatomy & histology