Divergent molecular signatures in fish Bouncer proteins define cross-fertilization boundaries

Krista R.B. Gert, Karin Panser, Joachim Surm, Benjamin S. Steinmetz, Alexander Schleiffer, Luca Jovine, Yehu Moran, Fyodor Kondrashov, Andrea Pauli*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

2 Scopus citations


Molecular compatibility between gametes is a prerequisite for successful fertilization. As long as a sperm and egg can recognize and bind each other via their surface proteins, gamete fusion may occur even between members of separate species, resulting in hybrids that can impact speciation. The egg membrane protein Bouncer confers species specificity to gamete interactions between medaka and zebrafish, preventing their cross-fertilization. Here, we leverage this specificity to uncover distinct amino acid residues and N-glycosylation patterns that differentially influence the function of medaka and zebrafish Bouncer and contribute to cross-species incompatibility. Curiously, in contrast to the specificity observed for medaka and zebrafish Bouncer, seahorse and fugu Bouncer are compatible with both zebrafish and medaka sperm, in line with the pervasive purifying selection that dominates Bouncer’s evolution. The Bouncer-sperm interaction is therefore the product of seemingly opposing evolutionary forces that, for some species, restrict fertilization to closely related fish, and for others, allow broad gamete compatibility that enables hybridization.

Original languageAmerican English
Article number3506
JournalNature Communications
Issue number1
StatePublished - 14 Jun 2023

Bibliographical note

Publisher Copyright:
© 2023, The Author(s).


Dive into the research topics of 'Divergent molecular signatures in fish Bouncer proteins define cross-fertilization boundaries'. Together they form a unique fingerprint.

Cite this