The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)


Is genetic variation a source of individual and populational differences in ovarian hormone concentrations?

VIRGINIA J. VITZTHUM1, JAMIE L. RENBARGER2, KENNETH P. NEPHEW3, LANG LI4, JONATHAN THORNBURG5, SLOAN R. WILLIAMS6 and TOBIAS DESCHNER7.

1Anthropology Department & The Kinsey Institute for Research in Sex, Gender, & Reproduction, Indiana University, Bloomington, 2Clinical Pharmacology & Pediatric Hematology/Oncology, IU School of Medicine, Indiana University, 3Medical Science Program, School of Medicine, Indiana University, 4The Center For Bioinformatics, IU School of Medicine, Indiana University, 5Department of Astronomy & IU Center for Spacetime Symmetries, Indiana University, Bloomington, 6Department of Anthropology, U Illinois, Chicago, 7Primatology, Max Planck Institute for Evolutionary Anthropology, Leipzig, Germany

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There is ample evidence of substantial inter-individual and inter-populational variation in the average concentrations of progesterone and estrogens in pre-menopausal women. But despite the prominence of ovarian functioning in models of human life history adaptations and the large body of work demonstrating that steroid concentrations are significant risk factors for breast and other cancers, little is known of the factors generating this hormonal variation.

Because energetic stressors influence temporal (inter-cycle) hormonal variation within an individual, it has been argued that energetic factors are principal determinants of natural (non-pathological) variation in hormone concentrations between individuals and populations. However, energetic stressors cannot readily explain the entirety of the substantial non-pathological variation in ovarian steroid concentrations within any single population nor the high progesterone concentrations in nomadic herders, who have relatively low energy intake and heavy workloads. These observations suggest that factors other than energetic stressors also generate significant natural variation in hormone concentrations.

In the present study, using data collected from pre-menopausal women drawn from three populations, we test the hypothesis that variations in the genes coding for the enzymes acting in steroid biosynthesis and metabolism are significant contributors to within and between populational variation in ovarian steroid levels. A finding that genetic variation is associated with substantial variation in hormone concentrations would raise questions regarding how the genotypic variation interacts with temporally and spatially varying environmental stressors, how evolutionary processes might have shaped this genotypic and phenotypic variation, and whether the variation is adaptive in one environment or another.

Supported by the US National Science Foundation; the Wenner-Gren Foundation; a Senior Fulbright Fellowship; the Office of the Vice Provost for Research, Indiana U, Bloomington; the Max Planck Institute for Evolutionary Anthropology; and the Kinsey Institute.

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