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Published on: November 11, 2011
Variation in clitoral length in rhesus macaques (Macaca mulatta)
Beatriz Goldschmidt1, Pedro H Cabello, Tatiana Kugelmeier
1Primatology Department, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil. bibi@fiocruz.br
Summary
Clitoromegaly in rhesus monkeys shows high variability and no link to fertility. Some male macaques sired primarily daughters without clitoris, suggesting complex inheritance patterns for genital development.
Area of Science:
- Primate reproductive biology
- Developmental endocrinology
- Comparative anatomy
Background:
- Clitoromegaly is a neonatal morphologic sign relevant for sexual determination in aberrant cases.
- Genital differentiation in rhesus monkeys (Macaca mulatta) is a prenatal process, largely complete by 80 days of gestation.
- Understanding clitoral size variations is crucial for primate reproductive studies.
Purpose of the Study:
- To determine typical clitoral size in normal rhesus monkeys.
- To investigate the effects of age and inheritance on clitoral size.
- To explore potential genetic factors influencing clitoral development in macaques.
Main Methods:
- Measurement of clitoral length in a cohort of normal rhesus monkeys.
- Statistical analysis to assess relationships between clitoral size, age, and fertility.
- Pedigree analysis to evaluate the inheritance patterns of clitoral presence/absence.
Main Results:
- Clitoral length exhibited significant variability among individuals.
- No correlation was found between clitoral length and fertility.
- No statistical association was observed between maternal and daughter clitoral presence.
- Some sires produced a disproportionate number of daughters lacking a clitoris.
Conclusions:
- Clitoral size in rhesus monkeys is highly variable and not indicative of fertility.
- While direct maternal inheritance of clitoral presence is not evident, some sires may influence the occurrence of clitoral absence in daughters.
- Further research is needed to elucidate the complex genetic and developmental mechanisms underlying clitoral development in primates.
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