Int. J. Dev. Biol. 48: 1079 - 1085 (2004)

https://doi.org/10.1387/ijdb.041912ts

Vol 48, Issue 10

The germ line lineage in ukigori, Gymnogobius species (Teleostei: Gobiidae) during embryonic development

Original Article | Published: 1 December 2004

Taiju Saito*^,1, Satoshi Otani², Takafumi Fujimoto¹, Tohru Suzuki³, Takako Nakatsuji⁴, Katsutoshi Arai1 and Etsuro Yamaha⁵

¹Laboratory of Breeding Science, Graduate School of Fisheries Science, Hokkaido University, ²Laboratory of Aquatic Biology, Faculty of Agriculture, Kinki University, ³Laboratory of Bioindustrial Informatics, Graduate School of Agriculture Science, Tohoku University, ⁴Department of Marine Biology, Graduate School of Marine Science and Technology, Tokai University and ⁵Nanae Fresh-Water Laboratory, Field Science Center for Northern Biosphere, Hokkaido University, Japan.

Abstract

In order to determine the origin and migration of ukigori primordial germ cells (PGCs), we observed the aggregation of vasa mRNA by whole mount in situ hybridization. To observe PGC migration in the germ layers, we analyzed HE-stained paraffin sections. The germ line lineages were derived from the edge of the first, second and third cleavage furrows. During subsequent cleavages, vasa mRNA aggregations were respectively taken into four to eight cells in each embryo and vasa expressing cells proliferated from the sphere stage. At the bud to early somitogenesis period, PGCs aligned from head to tail bud regions on both sides of the embryonic body. During the late somitogenesis period, PGCs mainly aggregated just underneath the body axis. After gut formation, PGCs aligned along both sides of the gut at the 4th- to 8th- somite regions. Finally, PGCs reached the genital ridge via the inside of the lateral plate mesoderm and dorsal peritoneum. These results suggest that localized patterns of vasa transcripts and the migration routes of PGCs are different among fish (Teleost) species, perhaps depending on the amount of germinal cytoplasm derived maternally and the timing of endoderm differentiation.

Keywords

primordial germ cell, PGC, vasa, cell lineage, ukigori