Origins, Dispersal, and Impact: Bidirectional Introgression Between Chinese and European Pig Populations

Area of Science:

• Animal Genetics
• Genomics
• Evolutionary Biology

Background:

• Human-mediated gene flow between Chinese and European pig populations is common.
• The reciprocal introgression patterns and the role of structural variations (SVs) are not well understood.

Purpose of the Study:

• To characterize bidirectional introgression between Chinese and European pigs.
• To investigate the contribution of SVs to genetic exchange and trait enhancement.

Main Methods:

• Whole-genome resequencing data from 418 pigs.
• Analysis of single-nucleotide polymorphisms (SNPs) and SVs.
• Validation using ancient pig genomes.

Main Results:

• Identified 3558 bidirectional introgressed genomic segments and 30 SVs.
• Found incomplete linkage disequilibrium between SVs and SNPs, limiting SNP-based analyses.
• Identified BMP2 haplotypes associated with improved body size, likely originating from ancient European pigs.

Conclusions:

• Bidirectional introgression significantly shapes genetic composition and traits in modern pigs.
• SVs are crucial for understanding genetic exchange and phenotypic variation.
• Ancient genomes provide insights into the evolutionary history of introgressed haplotypes.