POLYGENIC MUTATION IN DROSOPHILA MELANOGASTER: ESTIMATES FROM DIVERGENCE AMONG INBRED STRAINS

Area of Science:

• Evolutionary genetics
• Quantitative genetics
• Drosophila melanogaster research

Background:

• Understanding mutation rates is crucial for evolutionary studies.
• Drosophila melanogaster is a model organism for genetic research.
• Quantitative traits are influenced by multiple genes and environmental factors.

Purpose of the Study:

• To estimate the polygenic mutation rate (V_M) for abdominal and sternopleural bristle number in Drosophila melanogaster.
• To investigate the impact of mutation accumulation on quantitative traits over 100 generations.
• To analyze sex-specific effects and sex dimorphism in bristle number mutations.

Main Methods:

• Subdividing a highly inbred Drosophila melanogaster line into 25 replicate sublines.
• Independent maintenance of sublines for 100 generations with controlled population size.
• Estimating mutation rates using divergence among sublines and response to divergent selection.

Main Results:

• Mutation rates (V_M) were estimated as 3.3 × 10^-3 V_E for abdominal bristles and 1.5 × 10^-3 V_E for sternopleural bristles.
• Significant mutational variation in sex dimorphism for abdominal bristle number was observed.
• Sex × mutant effect interactions contributed substantially to the overall variance.

Conclusions:

• The study provides quantitative estimates of polygenic mutation rates for specific traits in Drosophila.
• Mutations affecting bristle number can have pleiotropic effects, influencing sex dimorphism.
• These findings contribute to understanding the genetic basis of quantitative trait evolution.