Germ cells are essential for gonadal development. As precursors of germ cells, primordial germ cells (PGCs) are particularly important for germline formation. However, the research on distribution patterns of PGCs in marine fish is very limited, especially for economic species. The vasa gene has been widely used as marker to identify PGCs origination and migration because of vasa RNA is a component of germ plasm. In this study, we isolated full-length vasa cDNA (Omvas and Pmvas) from marine medaka (Oryzias melastigma) and red seabream (Pagrus major), detected vasa transcripts in different tissues by RT-PCR and described vasa expression patterns during embryogenesis and gametogenesis by in situ hybridization. At the same time, we also explored the relationship between early distribution of germ plasm components and species evolution. The results demonstrated that deduced amino acid sequence of Omvas and Pmvas shared several conserved motifs of Vasa homologues and high identity with other teleost, and vasa transcripts were exclusively detected in early germ cells of gonad. During embryogenesis, vasa RNA of both fishes, like medaka (Oryzias latipes), failed to localize at cleavage furrows and distributed uniformly throughout each blastomere. This study firstly discovered that the marine economic fish, red seabream, lost vasa RNA early specific localization at cleavage furrows and distinctive distribution in germ cells. In addition, compared with other teleost, we found that early distribution of germ plasm might not relate to species evolution. This will improve our understanding of vasa localization modes in teleost, and facilitate fish germ cell manipulation.

生殖细胞对于性腺发育至关重要。作为生殖细胞的前体，原始生殖细胞（PGC）对于种系形成特别重要。然而，关于海洋鱼类中PGCs分布模式的研究非常有限，特别是对于经济物种而言。由于vasa RNA是种质的组成部分，因此vasa基因已被广泛用作鉴定PGC起源和迁移的标记。在这项研究中，我们从海洋（Oryzias melastigma）和红鲷（Pagrus major）中分离了全长vasa cDNA（Omvas和Pmvas），通过RT-PCR在不同组织中检测到vasa转录本，并进行了描述通过原位杂交在胚胎发生和配子发生过程中表达瓦萨表达模式。同时，我们还探索了种质组分早期分布与物种进化之间的关系。结果表明，推导的Omvas和Pmvas氨基酸序列具有瓦萨族同源基因的几个保守基序，并且与其他硬骨鱼具有高度同一性，并且仅在性腺的早期生殖细胞中检测到瓦萨基因的转录本。在胚胎发生过程中，两条鱼的脉管RNA都像medaka（Oryzias latipes），未能定位于卵裂沟，并在每个卵裂球中均匀分布。这项研究首先发现，海洋经济鱼类红鲷失去了vasa RNA的早期特异性定位，位于卵裂沟中，并且在生殖细胞中具有独特的分布。此外，与其他硬骨鱼类相比，我们发现种质的早期分布可能与物种进化无关。这将增进我们对硬骨鱼中vasa定位模式的理解，并有助于鱼类生殖细胞的操纵。