Mosaic individuals found in genetically manipulated northern pike (Esox lucius) using flow cytometry

The purpose of this study was to investigate abnormal larvae produced in th e experimental induction of gynogenetic northern pike (Esox lucius L.), usi ng a flow cytometry method. We reported for the first time the mosaic indiv iduals found in genetically manipulated northern pike. Two types of abnorma l larvae were obtained after eggs were fertilized with UV-irradiated sperm and then exposed to heat shock treatment. One type had malformations freque ntly associated with haploid syndrome and were proven to be haploids. The o ther type had a similar body size and appearance as diploids but with curve d body and a swirling swimming pattern. Individuals of the second type were proven to be mosaics containing both In (59.5 +/- 14.7% mean +/- SD) and 2 n (29.7 +/- 13.3%) cell populations. The ratio of In:2n cell populations ra nged from 80.6:10.6 to 38.5:44.7. There was no significant difference in th e relative nuclear DNA content and cell size between In and 2n cell populat ions of the mosaic individuals as compared to haploid cells and diploid cel ls, respectively. The nuclear DNA content of the northern pike was estimate d to be 2.07 +/- 0.06 pg (n = 10) given that rainbow trout has a red blood cell nucleus DNA content of 4.66 pg.