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Validating a Mitochondrial Sweep Accompanying the Rapid Spread of a Maternally Inherited Symbiont
Anne Duplouy1,2
1Insect Symbiosis Ecology and Evolution, Organismal and Evolutionary Biology Research Program, Faculty of Biological and Environmental Sciences, University of Helsinki, Helsinki, Finland. anne.duplouy@helsinki.fi.
Abstract:
Maternally inherited symbiotic bacteria that interfere with the reproduction of their hosts can contribute to selective sweeps of mitochondrial haplotypes through hitch-hiking or coordinate inheritance of cytoplasmic bacteria and host mitochondria. The sweep will be manifested by genetic variations of mitochondrial genomic DNA of symbiont-infected hosts relative to their uninfected counterparts. In particular, at the population level, infected specimens will show a reduced mitochondrial DNA polymorphism compared to that in the nuclear DNA. This may challenge the use of mitochondrial DNA sequences as neutral genetic markers, as the mitochondrial patterns will reflect the evolutionary history of parasitism, rather than the sole evolutionary history of the host. Here, I describe a detailed step-by-step procedure to infer the occurrence and timing of symbiont-induced mitochondrial sweeps in host species.
Insights
Maternally inherited bacteria can cause mitochondrial DNA sweeps in host populations. This reduces mitochondrial DNA polymorphism, impacting its use as a neutral genetic marker.
Area of Science:
- Evolutionary Biology
- Genetics
- Microbiology
Background:
- Maternally inherited symbionts can manipulate host reproduction.
- This manipulation can lead to selective sweeps of mitochondrial DNA (mtDNA).
- Such sweeps can affect the evolutionary history inferred from mtDNA.
Purpose of the Study:
- To describe a method for inferring symbiont-induced mitochondrial sweeps.
- To understand the impact of symbionts on host mitochondrial genetics.
- To assess the timing and occurrence of these sweeps.
Main Methods:
- Analyzing genetic variations in mitochondrial genomic DNA.
- Comparing symbiont-infected hosts with uninfected counterparts.
- Evaluating population-level mitochondrial DNA polymorphism relative to nuclear DNA.
Main Results:
- Symbiont infection leads to genetic variations in host mtDNA.
- Infected populations exhibit reduced mtDNA polymorphism compared to nuclear DNA.
- Mitochondrial patterns reflect parasitism history, not solely host evolution.
Conclusions:
- Symbiont-induced mitochondrial sweeps are detectable through genetic analysis.
- Reduced mtDNA polymorphism challenges its use as a neutral marker.
- The described procedure aids in studying symbiont-host co-evolutionary dynamics.
