AUTHOR=Razmi Komeil , Patil Jawahar G. 

TITLE=Primordial Germ Cell Development in the Poeciliid, Gambusia holbrooki, Reveals Shared Features Between Lecithotrophs and Matrotrophs

JOURNAL=Frontiers in Cell and Developmental Biology

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/cell-and-developmental-biology/articles/10.3389/fcell.2022.793498

DOI=10.3389/fcell.2022.793498

ISSN=2296-634X

ABSTRACT=<p>Metazoans exhibit two modes of primordial germ cell (PGC) specification that are interspersed across taxa. However, the evolutionary link between the two modes and the reproductive strategies of lecithotrophy and matrotrophy is poorly understood. As a first step to understand this, the spatio-temporal expression of teleostean germ plasm markers was investigated in <italic>Gambusia holbrooki</italic>, a poecilid with shared lecitho- and matrotrophy. A group of germ plasm components was detected in the ovum suggesting maternal inheritance mode of PGC specification. However, the strictly zygotic activation of <italic>dnd-β</italic> and <italic>nanos1</italic> occurred relatively early, reminiscent of models with induction mode (<italic>e.g.,</italic> mice). The PGC clustering, migration and colonisation patterns of <italic>G. holbrooki</italic> resembled those of zebrafish, medaka and mice at blastula, gastrula and somitogenesis, respectively—recapitulating features of advancing evolutionary nodes with progressive developmental stages. Moreover, the expression domains of PGC markers in <italic>G. holbrooki</italic> were either specific to teleost (<italic>vasa</italic> expression in developing PGCs), murine models (<italic>dnd</italic> spliced variants) or shared between the two taxa (germline and somatic expression of <italic>piwi</italic> and <italic>nanos1</italic>). Collectively, the results suggest that the reproductive developmental adaptations may reflect a transition from lecithotrophy to matrotrophy.</p>