Drosophila melanogaster egg-laying site selection offers a genetic model to study a simple form of value-based decision. We have previously shown that Drosophila females consistently reject a sucrose-containing substrate and choose a plain (sucrose-free) substrate for egg laying in our sucrose versus plain decision assay. However, either substrate is accepted when it is the sole option. Here we...

The sea urchin egg contains one or more tyrosine-specific protein kinase(s) which are active during the response of the egg to sperm fusion. Fertilization results in an 8-fold increase in the relative incorporation of [32P]orthophosphate into phosphotyrosine as compared to phosphoserine and phosphothreonine. Under defined in vitro conditions, plasma membranes from fertilized eggs incorporated 5...

During mammalian fertilization, sperm adhere to the extracellular coat of the egg, or zona pellucida, in a species-specific manner. In mouse, evidence suggests that sperm recognize and bind to specific oligosaccharide ligands within the zona pellucida glycoprotein, ZP3, via beta1,4-galactosyltransferase I (GalT I), a lectin-like receptor on the sperm surface. Although in vitro experiments using...

A specific sperm-egg interaction in the oviductal matrix is crucial for internal fertilization of the red-bellied newt, Cynops pyrrhogaster. An understanding of the molecular basis of this interaction is expected to elucidate the evolutionary history of internal fertilization in amphibians. Recently, deep sequencing technology has provided global gene information even in nonmodel animals, allow...

Initial sperm-egg binding in mammals involves recognition of glycosylated proteins of egg zonae by glycosylated proteins on sperm surfaces. Egg zona protein structure is relatively simple, and has been strongly conserved. Species specificity must reside in the carbohydrate modifications on the egg surface, and in the co-ordinated assembly of a unique cohort of sperm proteins at capacitation. Fr...

Where life-history stages overlap, there is the potential for physiological conflicts that might be important in mediating carryover effects. However, our knowledge of the specific physiological mechanisms underlying carryover effects remains rudimentary, and specific examples remain rare. Here we show that female macaroni penguins (Eudyptes chrysolophus) initiate vitellogenesis and yolk format...