Mitochondrial DNA Inheritance and Germline Purifying Selection: Insights From Drosophila.

Area of Science:

• Evolutionary Biology
• Genetics
• Molecular Biology

Background:

• Mitochondrial DNA (mtDNA) is prone to mutations due to its environment and maternal inheritance.
• Despite this, mtDNA integrity is remarkably conserved across evolution.
• Purifying selection in the female germline is known to limit deleterious mtDNA mutations.

Purpose of the Study:

• To synthesize literature on mtDNA integrity maintenance.
• To identify the primary mechanism driving purifying selection in the germline.
• To explore the role of replication competition in mtDNA evolution and genetic conflicts.

Main Methods:

• Literature synthesis with a focus on *Drosophila*.
• Analysis of developmentally orchestrated mitochondrial processes.
• Examination of bioenergetic performance coupling genome function to replication.

Main Results:

• Replication competition is the principal mechanism for mtDNA purifying selection in the germline.
• Developmental processes couple mitochondrial genome function to replication, enabling selection.
• Selection is based on the bioenergetic performance of individual mtDNA genomes during oogenesis.

Conclusions:

• Replication competition explains mtDNA integrity and evolution.
• This mechanism can generate genetic conflicts, including selfish mtDNA emergence.
• Replication competition shapes key features of mitochondrial genetics like maternal inheritance and bottlenecks.