Neuroendocrine Mechanisms of Reproduction in Songbirds

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This award is funded under the American Recovery and Reinvestment Act of 2009 (Public Law 111-5).The neuropeptide gonadotropin-releasing hormone-I (GnRH-I) is critical for the regulation of reproduction in all vertebrates. Study of the regulation of GnRH-I in passerine songbirds has been the focus of studies on subjects as diverse as photoperiodism, puberty, stress, nutrition, processing of auditory information, migration, global climate change and evolutionary biology. Until now, analysis of GnRH-I in songbirds has been limited to measurement of protein that can be visualized by immunocytochemical methods, so it has been impossible to fully determine how and when different environmental factors influence the synthesis of GnRH and thus affect reproduction. Measurement of messenger RNA (mRNA) regulation has been impossible because of lack of knowledge of the GnRH gene sequence, despite many attempts in the last 20 years to identify it. Thus, the relative roles of environmental, social, physiological and evolutionary influences upon songbird GnRH regulation have remained enigmatic. The recent cloning of GnRH-I cDNA from two songbird species will now permit molecular analysis of the regulation of songbird reproduction by physical, social and physiological cues, along with fine scale analysis of selection pressures acting upon the reproductive system of songbirds. It is expected that a paradigm shift in the understanding of the neuroendocrine control of reproduction at the molecular level will occur as a result of this proposal. Understanding of reproduction at this level is critical if captive breeding of endangered species is to be successful, and for effects of global change on reproduction in wild species to be understood.The intellectual merit of the results obtained includes advancement our understanding of the regulation of seasonal breeding in songbirds and the regulation of puberty in vertebrates as a whole. The broader impacts of the proposed research include training of minority undergraduate and graduate students in labs in the USA, encouragement of minority undergraduate participation in research and scientific meetings.