Structural genomic variation and migratory behavior in a wild songbird

Area of Science:

• Evolutionary Biology
• Genomics
• Ornithology

Background:

• Structural variants (SVs) are key drivers of genetic variation, with their roles in natural populations and phenotypic connections increasingly recognized.
• Understanding SVs in wild populations is crucial for deciphering evolutionary processes and trait adaptation.
• The Eurasian blackcap serves as a model system for studying adaptation and migration genetics.

Purpose of the Study:

• To characterize the genome-wide distribution, frequency, and fitness effects of SVs in the Eurasian blackcap.
• To investigate the genetic basis of seasonal migration using identified SVs.
• To correlate specific SVs with migratory traits such as direction, distance, and timing.

Main Methods:

• Haplotype-resolved genome assemblies were generated for 79 Eurasian blackcaps.
• Genome-wide SVs were identified, annotated, and their frequencies and fitness effects assessed.
• Genomic differentiation was used to detect SVs under selection related to migratory strategies.

Main Results:

• Over 15,000 SVs were detected, with many overlapping repetitive regions and showing signs of purifying selection.
• Insertions and deletions were common SV types, associated with genes involved in circadian rhythms and immune responses relevant to migration.
• A specific deletion on chromosome 27 was identified as a significant genetic factor influencing migratory direction in blackcaps.

Conclusions:

• Structural variants play a significant role in the evolution of natural populations.
• SVs contribute to the genetic architecture of complex traits like seasonal migration.
• This study provides novel insights into the genetic underpinnings of migratory behavior in birds.