The geometry and genetics of hybridization

Area of Science:

• Evolutionary biology
• Population genetics

Background:

• Hybrid fitness is crucial for understanding speciation.
• Factors influencing hybrid fitness include genome composition, environmental conditions, and population divergence history.

Purpose of the Study:

• To develop analytical predictions for hybrid fitness incorporating genome composition, environment, and divergence history.
• To connect these predictions to quantitative genetics and explore extensions of the model.

Main Methods:

• Utilizing Fisher's geometric model to derive analytical predictions.
• Applying the model to various population genetic parameters and divergence conditions (e.g., allopatry, parapatry, local adaptation, drift).

Main Results:

• Hybrid fitness decomposes into intrinsic admixture/heterozygosity effects and extrinsic parental adaptedness effects.
• Geometric distances quantify these effects and reflect divergence modes, showing convergence toward intrinsic isolation patterns.

Conclusions:

• The geometry of fitness landscapes offers a unifying framework for speciation research.
• The model provides interpretable geometric distances from cross data, aiding in understanding composite genetic effects.