Bidirectional Selection for Body Weight on Standing Genetic Variation in a Chicken Model

Area of Science:

• Genomics
• Animal Genetics
• Evolutionary Biology

Background:

• Experimental populations are crucial for understanding the genomic effects of selection.
• The Virginia body weight chicken lines offer a unique model for studying long-term, bidirectional selection impacts.

Purpose of the Study:

• To analyze within- and between-line genomic signatures of bidirectional selection in Virginia body weight chickens.
• To explore the genomic consequences of over 60 generations of divergent selection for body weight.

Main Methods:

• Detailed analysis of pooled genome resequencing data from selected chicken lines.
• Examination of genomic regions showing differentiation and signatures of selection.

Main Results:

• Bidirectional selection for body weight did not result in opposing genomic signatures between lines.
• Genomic signatures often showed a duality: homozygosity in one line and mosaic heterozygosity in the other.
• Haplotype mosaics suggest a complex demographic history including bottlenecks and introgressions.

Conclusions:

• Selection on standing genetic variation can lead to diverse genomic signatures.
• Haplotype mosaics in chicken lines reflect pre-existing genetic variation utilized by selection.
• Understanding these complex patterns is key to interpreting selection's genomic impact.