Beringia as a high-latitude engine of avian speciation.

Beringia is a biogeographically dynamic region that extends from northeastern Asia into northwestern North America. This region has affected avian divergence and speciation in three important ways: (i) by serving as a route for intercontinental colonisation between Asia and the Americas; (ii) by cyclically splitting (and often reuniting) populations, subspecies, and species between these continents; and (iii) by providing isolated refugia through glacial cycles. The effects of these processes can be seen in taxonomic splits of shallow to increasing depths and in the presence of regional endemics.

The genetic basis of plumage coloration and elevation adaptation in a clade of recently diverged alpine and arctic songbirds.

Trait genetic architecture plays an important role in the probability that variation in that trait leads to divergence and speciation. In some cases, speciation may be driven by the generation of novel phenotypes through the recombination of genes associated with traits that are important for local adaptation or sexual selection. Here, we investigate the genetic basis of three plumage color traits, and one ecological trait, breeding elevation, in a recent avian radiation, the North American rosy-finches (Leucosticte spp.

Phylogenomic Data Reveal Widespread Introgression Across the Range of an Alpine and Arctic Specialist.

Understanding how gene flow affects population divergence and speciation remains challenging. Differentiating one evolutionary process from another can be difficult because multiple processes can produce similar patterns, and more than one process can occur simultaneously. Although simple population models produce predictable results, how these processes balance in taxa with patchy distributions and complicated natural histories is less certain.