SYMPATRIC SPECIATION VIA HABITAT SPECIALIZATION DRIVEN BY DELETERIOUS MUTATIONS

Area of Science:

• Evolutionary Biology
• Speciation Research
• Population Genetics

Background:

• Habitat (host) races are considered a precursor to sympatric speciation.
• Previous theories posited strong adaptation trade-offs were necessary for habitat race evolution.
• These trade-offs involve alleles with opposing fitness effects across different habitats.

Purpose of the Study:

• To challenge the necessity of strong adaptation trade-offs for habitat race formation.
• To propose an alternative mechanism for habitat race evolution driven by habitat-specific genetic variation.
• To investigate the role of mutations with habitat-specific fitness effects in driving divergence.

Main Methods:

• Utilized deterministic two-locus and multilocus models.
• Simulated populations with genetic loci affecting fitness in one habitat but neutral in others.
• Incorporated deleterious mutations with habitat-specific fitness consequences.

Main Results:

• Demonstrated that genetic variation with habitat-specific effects can drive habitat race evolution.
• Showed that deleterious mutations with habitat-specific effects lead to indirect selection for habitat fidelity.
• Observed the evolution of genetically isolated populations using different habitats from a single panmictic population.

Conclusions:

• Strong adaptation trade-offs are not essential for the evolution of habitat races.
• Habitat-specific genetic variation, particularly from mutations, can promote divergence and isolation.
• The conditions favoring habitat race formation and potential sympatric speciation are less restrictive than previously assumed.