Spontaneous mosaicism occurred in normally fertilized and gynogenetically induced progeny of the kokanee salmon Oncorhynchus nerka

Abstract

In normally fertilized progeny of the kokanee salmon Oncorhynchus nerka, DNA content flow cytometry revealed that all the externally normal embryos were diploid, whereas abnormal embryos exhibited haplo-diploid, diplo-tetraploid and haplo-diplo-tetraploid mosaicisms, together with a few haploid and diploid individuals. When gynogenetic development was artificially induced by fertilization of eggs obtained from a female of the same kokanee brood stock with UV-irradiated sperm, haplo-diploid mosaics appeared most frequently. These mosaics were likely to happen by certain cytological events, such as meiotic or mitotic errors during the process of maturation, fertilization or early cleavage.