OVARIAN PHYSIOLOGY IN A NON-DOMESTICATED BIRD: MECHANISMS BEHIND THE ACCUMULATION AND VARIATION OF YOLK ANDROGENS IN HOUSE SPARROWS

Thesis (Ph.D.), Zoology, Washington State UniversityIn birds and other oviparous species, the accumulation of maternally-derived yolk androgens may represent an adaptive transgenerational information system. Researchers have found multiple effects of these yolk androgens on offspring in diverse oviparous species, in addition to many social and environmental factors that act on females to alter their yolk androgen levels. What is missing, however, is an understanding of the mechanism by which androgens accumulate in yolk, as well as knowledge of the physiological cause(s) of the immense intra-specific variation in yolk androgens. Using the drug tamoxifen to reduce levels of vitellogenin yolk precursors in house sparrows (Zoology, Washington State Universit