Genetic Correlations Among Dental, Mandibular, and Postcranial Dimensions in Rhesus Macaques (Macaca mulatta)

Area of Science:

• Primate evolutionary biology
• Bioanthropology
• Quantitative genetics

Background:

• Tooth dimensions typically scale with body size in primates, but the precise scaling patterns vary.
• Understanding these relationships can reveal evolutionary constraints on craniofacial and skeletal development.

Purpose of the Study:

• To estimate genetic and phenotypic correlations between dental, mandibular, and postcranial dimensions in rhesus macaques (Macaca mulatta).
• To assess if tissue type, anatomical region, or function influences these correlations, potentially acting as evolutionary constraints.

Main Methods:

• Measurements of teeth, mandibles, and postcrania from 362 adult rhesus macaques.
• Selection of humeral and femoral articular surfaces to represent primate body size.
• Estimation of genetic correlations using SOLAR and random skewers analyses to compare correlation matrices.

Main Results:

• The genetic correlation matrix showed high similarity to tissue type integration (tooth and bone) and anatomical region.
• Phenotypic correlation matrices were significantly similar to the genetic correlation matrix.
• Postcanine dental traits were highly heritable.

Conclusions:

• Dental traits were not closely genetically correlated with mandibular or postcranial dimensions in rhesus macaques.
• Scaling relationships between tooth and bone size may be maintained by non-genetic, environmental factors rather than genetic constraints.