a b s t r a c t
Diploid androgenotes were produced without egg irradiation in the loach, Misgurnus
anguillicaudatus. Eggs of wild-type diploid females were fertilized with diploid sperm of
a neo-tetraploid male and then cold-shock treated at 3 C (range, 0.5 C) for 30 minutes
just after fertilization to eliminate the female nucleus. After hatching, ploidy status of the
hatched larvae was analyzed by flow cytometry, which revealed putative diploid androgenotes
as well as larvae possessing other ploidies. Five independent microsatellite DNA
markers were genotyped to confirm all-male inheritance of the resultant diploid larvae.
The mean SD yield rate of diploid androgenetic larvae to total eggs used was 12.29
3.25% in the cold-shock group and 22.23 13.42% in the UV-irradiated group (P > 0.05).
No diploid androgenetic larvae were detected in the intact control group. To our knowledge,
this is the first report demonstrating successful induction of diploid androgenotes
without egg irradiation in fish.