| 摘要 |
An amphiploid aquatic animal having genomes A and B of different species which carries a sex chromosome of XXXY type with fertility. Among a large number of aquatic animals of the first hybrid generation kept in a closed system, a nonreductive sperm of a male and a nonreductive egg of a female are selected. Then the nonreductive egg is fertilized by the nonreductive sperm to thereby construct an amphiploid aquatic animal carrying a fertile sex chromosome of XXXY type. Because of having the XXXY-type sex chromosome, this animal can be crossed with a hybrid F1 egg AxBx and thus amphiploids in the next generation can be stablyconstructed via natural crossbreeding. Since individual chromosome sets of the same type are surely provided in the meiotic division, the characteristics of the first generation (F1) can be permanently sustained. Since there arises no genetic separation, each two sets of genomes in different types can be provided without fail and thus inbreed depression can be avoided even though relative mating is repeated. |
