Rev. Brasil. Genet. 15, 3, 535-546 (1992) (Brazil. J. Genetics) KARYOLOGICAL ANALYSIS AND IIDENTIFICATION OF HETEROCHROMOSOMES IN EXPERIMENTAL GYNOGENETIC
OFFSPRING OF RAINBOW TROUT (Oncorhynchus mykiss, WALBAUM)
N. Colihueque1 , P. Iturra1 ,N. Díaz2 , A. Veloso2 and F.Estay2
1.- Facultad de Medicina, Universidad de Chile, Santiago, Chile, and
2.- Facultad de Ciencias, Casilla 653
Expcrimental Oncorhynchus mykiss gynogenetic progenies were identified by karyotype analysis. Haploid embryoes were obtained by fertilizing eggs with 10 min irradiated UV sperm. Diploid
gynogenetic embryoes obtained by temperature shock showed two X chromosomes, identified with Hoechst 33258/AMD fluorecent stain. Mean survival rate of diploidized embryoes was 37% at hatching.
Chromosome number variability in the haploid embryoes suggests Robertsonian chromosome rearrangements in the maternal germ cell line, which can explain previously reported chromosome number
polymorphism trout.in rainbow.