Recent hybrids recapitulate ancient hybrid outcomes.

Area of Science:

• Evolutionary biology
• Genomics
• Speciation research

Background:

• Hybridization is a key evolutionary process.
• Understanding genomic consequences of hybridization is crucial.
• Effects of selection and recombination on hybrid genomes are not fully understood across different timescales.

Purpose of the Study:

• To investigate if selection and recombination have similar effects on hybrid genome composition in contemporary versus ancient hybrid lineages.
• To determine if patterns of introgression in contemporary hybrid zones can predict ancestry patterns in older hybrid populations.
• To examine the role of the Z chromosome in hybrid ancestry.

Main Methods:

• Comparative analysis of introgression patterns.
• Study of contemporary and ancient hybrid lineages in Lycaeides butterflies.
• Examination of ancestry on the Z chromosome.

Main Results:

• Patterns of introgression in a contemporary Lycaeides butterfly hybrid zone predict ancestry in older adjacent populations.
• A significant lack of Lycaeides melissa ancestry was observed on the Z chromosome in both contemporary and ancient hybrids.
• This pattern of reduced L. melissa ancestry on the Z chromosome was consistent across multiple ancient hybrid lineages.

Conclusions:

• Genomic ancestry patterns in ancient hybrids are predictable from contemporary hybrids.
• Selection and recombination appear to affect hybrid genomes consistently across different time scales.
• These findings suggest similar evolutionary forces operate during both speciation and species breakdown.