Transgressive segregation in mating traits drives hybrid speciation

Area of Science:

• Evolutionary biology
• Speciation research

Background:

• Hybridization generates genetic variation, potentially driving ecological speciation.
• The role of hybridization in speciation, particularly via non-adaptive mating traits, is not fully understood.

Purpose of the Study:

• To investigate how transgressive segregation of mating traits during hybridization can lead to incipient hybrid speciation.
• To identify conditions favoring the emergence and persistence of hybrid species.

Main Methods:

• Individual-based evolutionary simulations were employed.
• The simulations modeled recurrent hybridization with immigration from parental lineages.

Main Results:

• Incipient hybrid speciation was most frequent under moderate, recurrent hybridization.
• Recurrent hybridization fueled rapid, stochastic evolution of mating phenotypes, leading to reproductive isolation.
• Excessive hybridization hindered reproductive isolation by increasing mating trait variation.

Conclusions:

• Recurrent transgressive segregation of mating phenotypes offers a mechanism for hybrid speciation.
• This process can explain radiations involving limited ecological divergence.