Speciation in peripheral populations: effects of drift load and mating systems

Area of Science:

• Evolutionary Biology
• Speciation Research
• Population Genetics

Background:

• Peripheral population speciation is a key model for speciation with gene flow.
• Previous models often overlook specific challenges in peripatric scenarios.

Purpose of the Study:

• To identify and analyze additional impediments to peripatric speciation compared to parapatric speciation.
• To explore the consequences of unidirectional gene flow and genetic load on mating systems and speciation completion.

Main Methods:

• Theoretical modeling of speciation processes.
• Analysis of genetic drift and selection pressures in peripheral populations.
• Simulation of different mating schemes and their impact on reproductive isolation.

Main Results:

• Unidirectional gene flow in peripatric speciation lacks selection for assortative mating on the mainland.
• Genetic load in small peripheral populations can lead to extinction or favor reduced assortative mating to avoid inbreeding.
• Outcomes include stable intermediate assortment or cyclical phases of hybridization and isolation.

Conclusions:

• Peripatric speciation may be less robust than previously assumed due to specific genetic and mating system dynamics.
• The interplay between gene flow, genetic load, and mating behavior critically influences speciation success.
• Further research is needed to refine models of speciation with gene flow.