Finding Hybrid Incompatibilities Using Genome Sequences from Hybrid Populations.

Area of Science:

• Evolutionary biology
• Genetics
• Genomics

Background:

• Natural hybrid zones are crucial for studying ongoing speciation.
• Postzygotic reproductive isolation is often driven by epistatic interactions (hybrid incompatibilities).

Purpose of the Study:

• To develop a method for detecting epistatic selection against hybrid incompatibilities using genome sequence data.
• To analyze the site frequency spectrum (SFS) of polymorphisms in hybrid populations.

Main Methods:

• Individual-based simulations were conducted using SLiM.
• The study focused on the genome-wide and local site frequency spectrum (SFS).
• A statistical method was developed to identify genomic regions with incompatibility loci by comparing local and genome-wide SFS.

Main Results:

• The genome-wide SFS in hybrid populations exhibits a distinct shape due to continuous migration.
• Epistatic selection against incompatibilities locally distorts the SFS, similar to selective sweeps.
• The developed method successfully detects recessive and codominant incompatibilities under various conditions.

Conclusions:

• The new statistical method effectively identifies genomic regions harboring hybrid incompatibilities.
• This approach leverages whole genome sequence data and does not require prior demographic information.
• The method is applicable to any hybrid zone between nascent species.