Genetic and extragenetic variance in motor performance

Area of Science:

• Behavioral Genetics
• Motor Control
• Human Performance

Background:

• Individual differences in psychomotor skills are influenced by both genetic and environmental factors.
• Understanding the relative contributions of nature versus nurture is crucial for optimizing training and interventions.
• Twin studies provide a powerful methodology for disentangling genetic and environmental influences.

Purpose of the Study:

• To estimate the contribution of genetically controlled phenotypic variance to psychomotor individuality.
• To investigate how genetic control over motor performance changes with practice.
• To differentiate between genetic and non-genetic factors influencing motor learning.

Main Methods:

• Utilized a simple additive model of genes and environment.
• Analyzed intrapair similarities in 35 monozygotic (MZ) and 35 dizygotic (DZ) like-sexed twin pairs.
• Subjects performed 50 trials on a pursuit rotor apparatus with a defined work-rest schedule.

Main Results:

• A larger proportion of individual differences in motor performance was attributed to genetic factors compared to non-genetic factors under similar environmental conditions.
• The strength of genetic control over psychomotor performance systematically decreased over the course of practice.
• A monotonic trend was observed in the diminishing genetic influence throughout the practice trials.

Conclusions:

• Genetic factors play a substantial role in initial psychomotor individuality.
• The influence of genetics on motor performance diminishes with extensive practice, suggesting environmental or learning-specific factors become more dominant.
• Motor skill acquisition involves a dynamic interplay between genetic predispositions and environmental learning experiences.