Induction of hexaploid by hot water treatment of inseminated eggs in the silkworm, Bombyx mori
1996
Yokoyama, T. (Tokyo Univ. of Agriculture and Technology, Koganei (Japan). Faculty of Technology) | Suzuki, M. | Chen, F.S. | Abe, H. | Nakagaki, M. | Oshiki, T.
When inseminated eggs given by the cross [Ge x Cambodge (+re/+re, +pY/+p+Y)] x re9 (re/re, pS+Y/pS+Y) were treated with hot water at 46 degrees C for 18 min shortly after oviposition, 18 larvae hatched from normally pigmented eggs. All were females with the dominant larval characters of both parents and survived until the adult stage. When mated with diploid males (re9), 12 of the females deposited eggs which were irregular in shape and size and unhatchable, suggesting that most of the females were triploid (ZZW). Unexpectedly, 2 of the females gave big and fertilized eggs after mating with diploid males (re9). The number of sex-heterochromatin bodies per nucleus from the sucking stomach cells of these 2 moths was 2. The nuclear DNA content per embryonic cells of the big eggs measured by flow cytometry was 2 times larger than that of the diploid progeny. These results indicate that the females were hexaploid of the ZZZZWW type, which might be due to the duplication of the ZZW triploid
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