Doctoral Dissertation Improvement: Hormones and Body Size Evolution in Old World Monkeys

University Of Illinois At Urbana-Champaign, Urbana IL

Investigators

Abstract

This study investigates the hormonal causes of differences in body size in Old World monkeys, with an emphasis on baboons and their close relatives. Body size is an extremely important variable in biology and in biological anthropology. Analyses of why size differs in Old World monkeys can shed light on a number of important scientific questions regarding patterns of growth and development. In addition, recent advances in endocrinology have challenged longstanding ideas about the role of hormones in growth control, and ultimately in resulting adult size. This research project addresses hypotheses that make predictions about hormonal control of growth in primates, with direct application to human growth and development. Specifically, the research addresses three primary hypotheses. First, it is expected that serum levels of growth-regulatory hormones during development are independent of adult body size, both inter- and intraspecifically. Second, it is expected that tissue expression of hormones and receptor number and affinity covary with size change and adult size, both inter- and intraspecifically. Third, the research evaluates the hypothesis that hormones involved in body mass development provide reliable information about phylogeny, and are therefore mechanisms by which developmental homology may occur or be recognized. These hypotheses are tested in the context of emerging models of hormone action that prioritize processes at the tissue level, and suggest a secondary role for endocrine axes. Analyses are conducted using a large set of serum samples from captive primates. Data will be analyzed quantitatively through a variety of sophisticated statistical techniques. These analyses will help determine the relations of growth hormones to growth, development, as well as to adult size and shape. In addition, the research has direct applications to human biomedical contexts because the primates analyzed may serve as extremely important models of human hormonal growth and development. Implications for ageing research will also be considered.