Predicting nuclear gene coalescence from mitochondrial data: the three-times rule

Area of Science:

• Evolutionary biology
• Population genetics
• Molecular evolution

Background:

• Coalescence theory explains nuclear gene tree monophyly but requires unknown effective population sizes.
• Neutral theory predicts nuclear monophyly evolves slower than mitochondrial DNA (mtDNA) due to slower genetic drift.
• Mitochondrial DNA variation is extensively studied, but its predictive power for nuclear loci is unclear.

Purpose of the Study:

• To investigate if mitochondrial DNA data can predict nuclear gene tree coalescence patterns.
• To test a proposed "three-times rule" for predicting nuclear monophyly based on mtDNA data.
• To establish an empirical benchmark for evaluating evolutionary processes across multiple genetic loci.

Main Methods:

• Compared neutral theories of mitochondrial and nuclear loci coalescence.
• Defined a "coalescence ratio" using mitochondrial branch length and intraspecific mtDNA diversity.
• Tested the "three-times rule" with mitochondrial and nuclear intron data from seven cetacean species.

Main Results:

• Species with high coalescence ratios exhibited nuclear monophyly.
• Species with low coalescence ratios showed polyphyletic nuclear gene trees.
• The "three-times rule" showed general agreement with observed patterns in whales and dolphins.

Conclusions:

• The "three-times rule" provides a potential method to predict nuclear gene tree patterns using readily available mtDNA data.
• This rule can serve as an empirical benchmark for evolutionary studies, potentially detecting selection.
• Mitochondrial DNA data can be leveraged to infer nuclear evolutionary dynamics.