mtDNA sequence, phylogeny and evolution of laboratory mice

Area of Science:

• Evolutionary Biology
• Genetics
• Animal Models

Background:

• Laboratory mice are indispensable in biomedical research.
• Understanding their evolutionary history is crucial for interpreting research findings.
• Mitochondrial DNA (mtDNA) serves as a valuable marker for phylogenetic studies.

Purpose of the Study:

• To investigate the phylogeny and evolution of laboratory mice.
• To trace the maternal lineage of classic inbred strains, outbred stocks, and wild-derived strains.
• To analyze the evolutionary pressures on mtDNA in laboratory mice over the last century.

Main Methods:

• Sequencing of mitochondrial DNA (mtDNA) from various laboratory mouse strains.
• Phylogenetic analysis to reconstruct evolutionary relationships.
• Dating divergence events using molecular clock methods.
• Analysis of mtDNA polymorphisms to infer selection pressures.

Main Results:

• Most classic outbred stocks and inbred strains share a single mtDNA ancestor.
• Phylogenetic analysis supports M. m. castaneus/M. m. domesticus as sister subspecies.
• The divergence between these subspecies and M. m. musculus occurred approximately 493,000 years ago.
• mtDNA polymorphisms in recent laboratory mice indicate relaxed purifying selection.

Conclusions:

• Laboratory mouse strains have a common maternal origin, simplifying some genetic interpretations.
• The evolutionary history aligns with established subspecies relationships.
• Recent accumulation of mtDNA polymorphisms suggests altered selective pressures in the laboratory environment.