Committing the primordial germ cell: An updated molecular perspective

The germ line is a crucial cell lineage that is distinct from somatic cells, and solely responsible for the trans-generational transmission of hereditary information in metazoan sexual reproduction. Primordial germ cells (PGCs)-the precursors to functional germ cells-are among the first cell types to be allocated in embryonic development, and this lineage commitment is a critical event in partitioning germ line and somatic tissues. Classically, mammalian PGC development has been largely informed by investigations on mouse embryos and embryonic stem cells. Recent findings from corresponding nonrodent systems, however, have indicated that murine PGC specification may not be fully archetypal. In this review, we outline the current understanding of molecular mechanisms in PGC specification, emphasizing key transcriptional events, and focus on salient differences between early human and mouse PGC commitment. Beyond these latest findings, we also contemplate the future outlook of inquiries in this field, highlighting the importance of comprehensively understanding early fate decisions that underlie the segregation of this unique lineage. This article is categorized under: Developmental Biology > Stem Cell Biology and Regeneration Biological Mechanisms > Cell Fates Physiology > Mammalian Physiology in Health and Disease.