Timing of Postfertilization Pressure Shock Treatment for the Production of Mitotic Gynogens in Six Salmonid Species

Doubled haploid gynogens are individuals whose genetic material consists of two identical maternal chromosome sets and who lack paternal contributions. These can be useful in whole-genome sequence assembly to eliminate allelic variation an individual that otherwise complicates the discrimination SNPs paralogs regular diploids. This is particularly important salmonid species, which have extensive remnants ancestral duplication. Further, doubled fully homozygous used generate clonal lines. Here, successful timing was determined for late pressure shocking producing five Oncorhynchus species (Chinook Salmon O. tshawytscha, Coho kisutch, Chum keta, Pink gorbuscha, Sockeye nerka) one Salvelinus (domesticated Artic Char alpinus). For this study, sperm treated with UV irradiation inactivate nuclear DNA fertilize eggs. The resulting zygotes were shocked at various times following fertilization form embryos via inhibition first cell division (mitotic gynogenesis). At incubation temperature 10.5°C, postfertilization shock maximal survival confirmed 2.41–2.83 accumulated thermal units (ATUs) Salmon, 2.63–2.84 ATUs 2.84–3.06 2.19 2.63–3.06 Chinook whereas Arctic a time 2.29–2.54 4°C successful. Survival fry stage ranged from less than 1% 11.7%. Survivors genotyped using microsatellite markers assess nonpaternity homozygosity found 92.5% when averaged across all treatments species. Mitotic gynogenetic produced six subsequent studies sequences Chinook, Coho, Chum, salmons.