One of the first lineage to arise during embryogenesis is the germline, the lineage that gives rise to oocytes and sperm. The embryonic germline exhibits several unique features, including delayed activation of transcription in the nucleus and large RNA granules in the cytoplasm. We are studying how these features make the germline unique and different from all other cell types in our bodies.
https://www.ncbi.nlm.nih.gov/pubmed/29111977