Insights into Early Ontogenesis of : RNA Extraction, Housekeeping Gene Validation and Transcriptional Expression of Important Primordial Germ Cell and Sex-Determination Genes

The challenge in extracting high-quality RNA impedes the investigation of the transcriptome of developing salmonid embryos. Furthermore, the mRNA expression pattern of important PGC and SD genes during the initial embryonic development of is yet to be studied. So, in the present study, we aimed to isolate high-quality RNA from eggs and developing embryos to check , , , , , , , and expression by qPCR. Additionally, four HKGs (, , and were validated to select the best internal control for qPCR. High-quality RNA was extracted, which was confirmed by spectrophotometer, agarose gel electrophoresis and Agilent TapeStation analysis. was chosen as a reference gene because it exhibited lower intra- and inter-sample variation. transcripts were expressed in all the developmental stages, while was expressed only up to 40 d°C. was expressed in later stages and remained at its peak for a shorter period, while showed an irregular pattern of mRNA expression. The mRNA expression levels of SD genes were observed to be upregulated during the later stages of development, prior to hatching. This study presents a straightforward methodology for isolating high-quality RNA from salmon eggs, and the resulting transcript profiles of significant PGC and SD genes in could aid in improving our comprehension of reproductive development in this commercially important species.