Temperature preference can bias parental genome retention during hybrid evolution

Area of Science:

• Evolutionary Biology
• Genomics
• Microbiology

Background:

• Interspecific hybridization generates genetic variation, crucial for adaptation.
• Environmental pressures can shape the evolutionary trajectory of hybrid genomes.

Purpose of the Study:

• To investigate how temperature and nutrient limitation affect parental genome representation in yeast hybrids.
• To identify genomic regions and genes involved in hybrid adaptation to cold and limited nutrients.

Main Methods:

• Evolving Saccharomyces cerevisiae x Saccharomyces uvarum hybrids under nutrient limitation at 15°C for 200 generations.
• Analyzing changes in parental allele representation and identifying loss of heterozygosity events.
• Investigating the role of specific genes, like PHO84, in adaptation.

Main Results:

• Cold adaptation led to the loss of S. cerevisiae alleles in favor of cryotolerant S. uvarum alleles in specific genomic regions.
• A genotype by environment interaction was observed on chromosome XIII, with allele loss dependent on parental species and evolution temperature.
• The high-affinity phosphate transporter gene PHO84 was identified as a key driver of directional adaptation due to a temperature-dependent fitness benefit.

Conclusions:

• Environmental conditions, particularly temperature, significantly impact the evolution of hybrid genomes.
• Specific genes like PHO84 can confer a fitness advantage, driving directional selection in hybrids.
• This study provides insights into the forces governing genome evolution post-hybridization and hybrid persistence.