Hybrid sterility increases with genetic distance in snubnose darters (Percidae: Etheostoma)

摘要

The process of speciation is often synonymous with the evolution of reproductive isolation, and the tempo at which reproductive barriers evolve can provide insight into the underlying mechanisms of divergence. Darters are a diverse group of North American freshwater fish in which behavioral isolation appears to evolve rapidly; however, little is known about hybrid sterility among darter species. Here, six allopatric pairs of darter species were hybridized via in vitro fertilization and offspring were reared to reproductive age. Hybrid sterility appears more pronounced in male hybrids. Additionally, levels of hybrid sterility increase with genetic distance across species pairs. Understanding sex determination and sex-specific gene expression in darters will provide further insight into the evolution of hybrid sterility.