Gene by environmental interactions affecting oxidative phosphorylation and thermal sensitivity.

Area of Science:

• Evolutionary biology
• Genomics
• Metabolic physiology

Background:

• Oxidative phosphorylation (OxPhos) is crucial for ATP production, involving both nuclear and mitochondrial genomes.
• Mitonuclear interactions can influence organismal traits but are understudied within natural populations.
• Fundulus heteroclitus populations exhibit admixed northern and southern mitochondrial haplotypes with differing nuclear allele frequencies.

Purpose of the Study:

• To investigate the impact of mitochondrial haplotype and associated nuclear differences on OxPhos parameters within a single Fundulus heteroclitus population.
• To determine how environmental temperature influences mitonuclear interactions affecting OxPhos function.

Main Methods:

• Analysis of six OxPhos parameters in Fundulus heteroclitus with distinct mitochondrial haplotypes.
• Experimental acclimation to different temperatures (12°C and 28°C) followed by acute temperature challenges.
• Assessment of mitochondrial genotype-specific responses to thermal stress.

Main Results:

• Significant functional differences in OxPhos were observed between northern and southern mitochondrial genotypes.
• The southern mitochondrial genotype showed a pronounced acute response to high temperatures, unlike the northern genotype.
• Temperature acclimation modulated the acute temperature effects on OxPhos, particularly the relative contribution of Complex I and II.

Conclusions:

• Mitochondrial haplotype and associated nuclear factors drive significant variation in OxPhos function within a natural population.
• Gene-environment interactions, specifically temperature, critically influence mitonuclear compatibility and metabolic responses.
• These findings highlight the importance of considering both genetic background and environmental context in understanding metabolic adaptation.