Meeting Abstract

2.9  Jan. 4  Yolk steroids regulate crypic back patterns in a lizard LANCASTER, LT*; MCADAM, AG; WINGFIELD, JC; SINERVO, BR; Univ. of California, Santa Cruz; Michigan State Univ.; Univ. of Washington; Univ. of California, Santa Cruz lesley@biology.ucsc.edu

We investigated the role of maternally derived yolk steroids in modulating back pattern elements in side-blotched lizards (Uta stansburiana). These lizards exhibit alternative social strategies associated with alternative throat colors (Orange, Blue or Yellow coded by the OBY locus). Previously unreported, the species also exhibits a polymorphism for back pattern, which serves a cryptic, anti-predator function. Here we show that back pattern variants are induced by prenatal exposure to yolk steroids. Yolk steroid levels varied as a function of the dam�s social environment (local OBY allele frequencies). Effects of yolk steroids on dorsal markings in progeny in turn depended on progeny OBY genotype. Progeny with steroid-modulated back patterns experienced fitness benefits compared to non-induced progeny. Our results reveal a novel effect of yolk steroid exposure (effects on crypsis are, to our knowledge, previously undescribed in the endocrine maternal effect literature). The effects on progeny of similar yolk steroid concentrations varied as a function of the dam�s inducing cue and progeny genotype, suggesting that effects of maternal hormones may be more versatile than previously thought. Because we describe epigenetic inheritance mechanisms contributing to the reliable, context-dependent formation of adaptive trait complexes (throat color and back pattern), our results also support the broader hypothesis that increasing complexity in biological systems corresponds to increasing complexity in inheritance mechanisms.