Selection against accumulating mutations in niche-preference genes can drive speciation

Area of Science:

• Evolutionary Biology
• Genetics

Background:

• Sympatric speciation traditionally involves disruptive selection on ecological genes and reinforcement.
• Existing models focus on competition driving ecological specialization and subsequent reproductive isolation.

Purpose of the Study:

• To propose and model a new mechanism for sympatric speciation.
• To investigate the role of resource recognition and preference traits in speciation.

Main Methods:

• Development of an evolutionary model simulating selection on resource traits.
• Analysis of gene-level regulatory functions and allele silencing.
• Modeling of assortative mating and mutation accumulation.

Main Results:

• Speciation occurs in three phases: specialization establishing phenotypic polymorphism with silent alleles, assortative mating driven by resource preference, and post-zygotic isolation via accumulated mutations.
• Silent alleles accumulate deleterious mutations in a Bateson-Dobzhansky-Muller manner.
• Assortative mating prevents expression of harmful mutations in parents, facilitating lineage division.

Conclusions:

• A novel pathway for sympatric speciation is identified, driven by resource specialization and preference.
• Gene regulatory evolution, including allele silencing, plays a crucial role.
• This mechanism establishes pre- and post-zygotic isolation without initial strong competition.