The Distribution of the Germ Plasm Gene germes among Anurans

Abstract

The germes gene is a marker of germ plasm and primordial germ cells (PGC). It is described for the African clawed frog Xenopus laevis. Overexpression of its mutant form negatively affects the formation and migration of PGC. However, it was unknown until now how widely this gene is represented in animals of different phylogenetic groups. For this work, the authors performed bioinformatic analysis of genomic and transcriptome sequences of animals with germ plasm. We found out that the germes homologs are present only in representatives of the genera Xenopus and Hymenochirus of the family Pipidae (order Anura). The obtained results were confirmed by RT-PCR analysis of the expression of the germes orthologs in the ovaries of six representatives of different Anura families. Phylogenetic analysis of cloned sequences of the germes homologs suggests the appearance of this gene in the ancestors of Pipidae and its secondary loss in the genus Pseudohymenochirus. It is also shown that the amino acid sequences of the functional domains of the Germes protein are rather conservative.