Digest: The impact of egg and sperm proteins on sea urchin reproductive compatibility.

Abstract

Levitan and Hao (2025) investigate reproductive isolation in sea urchins using fertilization assays, pinpointing amino acid substitutions that may cause isolation between species. Genotyping wild urchins showed that a single substitution in an egg protein could limit hybridization where two species coexist. Their findings shed light on how interspecific isolation can evolve and manifest in the wild, with eggs potentially under stronger selection to reduce hybridization due to higher costs.