Evolution of the germline mutation rate across vertebrates

Area of Science:

• Evolutionary Biology
• Genomics
• Comparative Biology

Background:

• The germline mutation rate is a fundamental parameter influencing genome evolution.
• Understanding the factors that shape mutation rate evolution is crucial but remains poorly understood.
• Previous studies often used varied methodologies and focused on single species.

Purpose of the Study:

• To quantify and compare germline mutation rates across a diverse range of vertebrate species.
• To identify the key life-history traits and population-level factors that influence mutation rate variation.
• To provide ecological insights into the evolutionary dynamics of mutation rates.

Main Methods:

• Sequencing and comparing high-coverage genomes from 151 parent-offspring trios across 68 vertebrate species (mammals, fishes, birds, reptiles).
• Analyzing pedigree-based germline mutation rates.
• Correlating mutation rates with life-history traits (generation time, age at maturity, fecundity) and effective population size.

Main Results:

• Per-generation mutation rates vary by a factor of 40 across species.
• Mutation rates are higher in males than females in mammals and birds, but not in reptiles and fishes.
• Shorter generation times, earlier age at maturity, and higher fecundity are associated with higher mutation rates.
• Species with larger effective population sizes exhibit lower per-generation mutation rates.
• Domesticated animals show exceptionally high yearly mutation rates, linked to selection for shorter generation times.

Conclusions:

• Life-history traits, particularly generation time, are major drivers of mutation rate evolution in vertebrates.
• Effective population size may play a role in modulating mutation rates, supporting the drift barrier hypothesis.
• Comparative genomics of mutation rates offers significant ecological insights into evolutionary processes.