Understanding the genetic bases of phenotypic variation is one of the most challenging topics faced by evolutionary biologists. Recently next-generation sequencing technologies (NGS) have brought into focus exciting technological advances to cover these aims, to the point that new disciplines such as Evolutionary and Ecological Genomics have recently emerged. Here, we propose to take advantage of one of the very few well-described ring species, the greenish warbler Phylloscopus trochiloides, to embark on the search of genomic regions involved in adaptive evolution and speciation. Ring species are enormously valuable model systems in evolutionary biology due to their scarcity and to the fact that they illustrate how evolution works in living populations. The greenish warbler was once confined to the southern border of its distribution range and then expanded northwards bordering the Himalayas through two independent pathways. Two distinct forms of Greenish warblers now coexist in Central Siberia without interbreeding and are connected by a long chain of gradually changing populations encircling the Tibetan Plateau. Interestingly, phenotypic studies have documented both parallel evolution and strong differentiation in phenotypic traits around the ring. Through the isolation of thousands of genetic markers (Single Nucleotide Polymorphisms) from NGS data we intend to investigate the genetic basis of parallel and divergent evolution across the six different forms comprising the superspecies complex. Specifically, we are interested in disentangling the partial role of neutral evolutionary forces and natural selection during speciation processes. The genetic data obtained in this respect might also add valuable information regarding the chromosomal location of genomic regions of adaptive significance and the impact of variation at protein-coding loci and regulatory elements on evolutionary processes.