"Understanding the genetic basis of phenotypic traits is of fundamental importance in evolutionary and conservation biology, but especially in the field of speciation. Hybrid speciation essentially involves fusion and stabilization of two distinct genomes accompanied by reproductive isolation from the parental counterparts. I will investigate how genetic architecture of secondary sexual traits evolves during hybrid speciation and the consequences this may have on speciation. The Italian Sparrow (Passer italiae) is a stabilized and uniform hybrid taxon that originated from past events of hybridization between two divergent parental species, the House Sparrow (P. domesticus) and the Spanish Sparrow (P. hispaniolensis). The two parental species differ in a number of functionally important traits, including melanin-based plumage coloration. This system provides excellent opportunities to study the genetic architecture of secondary sexual traits, as adult male breeding plumage differs between species. These plumage traits are targets for mate choice in sparrows, and are hence also likely to function in species recognition. More specifically, I will study how the genetic structure of plumage ornamentations in a bird species changes during its origin through hybridization of two parental species. This goal will be achieved by using a combination of cutting-edge methods in quantitative genetics and molecular genetics."