Testing the genomic overlap between intraspecific mating traits and interspecific mating barriers

Area of Science:

• Evolutionary biology
• Population genomics
• Speciation research

Background:

• Interspecific mating traits drive rapid evolution and reproductive isolation between species.
• Reinforcement can strengthen mating barriers during secondary contact.
• The role of loci underlying intraspecific trait variation in interspecific barrier formation is unclear.

Purpose of the Study:

• Investigate whether loci associated with intraspecific variation in mating traits are co-opted in the formation of interspecific mating barriers.
• Identify genetic loci contributing to intraspecific variation in sexual signals (song, pheromones) in *Teleogryllus oceanicus*.
• Identify candidate loci responsible for reproductive isolation between *Teleogryllus oceanicus* and *Teleogryllus commodus*.

Main Methods:

• Population genomics approach using natural populations of Australian cricket sister species (*T. oceanicus* and *T. commodus*) in a contact zone.
• Identification of loci associated with intraspecific variation in advertisement song and cuticular hydrocarbon (CHC) pheromones in *T. oceanicus*.
• Identification of candidate interspecific barrier loci based on elevated allelic divergence between the two species.

Main Results:

• Genes with high allelic divergence between species were enriched for neurological functions.
• Only two CHC-associated genes overlapped with interspecific candidate barrier loci; CHC loci showed strong selective constraints.
• Ten intraspecific song-associated genes showed high genetic differentiation between species, with two exhibiting high genomic divergence.

Conclusions:

• Limited overlap between loci for intraspecific mating traits and interspecific barrier loci suggests distinct genetic architectures.
• The genetic basis of reproductive isolation may not heavily rely on the co-option of genes driving variation within species' sexual signals.
• Findings provide insights into the genetic mechanisms underlying speciation and the evolution of reproductive isolation.