Clines with asymmetric migration.

Area of Science:

• Population Genetics
• Evolutionary Biology
• Mathematical Biology

Background:

• Examines allele maintenance in a one-dimensional habitat pocket.
• Considers a diffusion model of migration and selection without mutation or drift.
• Assumes homogeneous, genotype-independent migration and constant population density.

Purpose of the Study:

• To investigate the consequences of asymmetric dispersion on allele maintenance.
• To determine how migration patterns influence genetic polymorphism.
• To analyze the conditions for maintaining alleles in localized environmental pockets.

Main Methods:

• Utilizes a diffusion model for migration and selection.
• Restricts analysis to a single diallelic locus in a monoecious population.
• Employs both analytical and numerical studies.

Main Results:

• Outward-biased dispersion eases allele maintenance in pockets compared to symmetric migration.
• Inward-biased dispersion intensifies conditions for polymorphism.
• Asymmetric migration decreases polymorphism probability when an allele is deleterious in surrounding regions.
• Population density influences gene frequency determination, with denser areas being more impactful.

Conclusions:

• Asymmetric migration significantly alters allele dynamics and polymorphism probability.
• Environmental pocket density plays a crucial role in allele maintenance.
• The criterion for cline existence is invariant to asymmetry direction, but the cline itself is not.