Speciation, where one species splits into two, has long been a focus of evolutionary research. A new study almost 20 years in the making suggests that the opposite—speciation reversal, where two distinct lineages hybridize and eventually merge into one—may be just as important.
In the paper, published in Nature Communications, Smithsonian Conservation Biology Institute scientists and partners report some of the strongest evidence yet of this phenomenon in two lineages of common ravens.
Researchers examined genomic data from hundreds of ravens across North America, a challenging effort that proved to be worthwhile. “Next-generation genomic techniques are revealing more and more examples of species with hybrid genomes,” explains Anna Kearns, postdoctoral fellow with SCBI’s Center for Conservation Genomics and the study’s lead author.
In fact, throughout history this natural evolutionary process of speciation reversal has probably occurred in hundreds or thousands of lineages across the planet
When UMBC professor of biological sciences Kevin Omland, one of the paper’s authors, first started down this road in 1999, common ravens were considered a single species. A year later, he reported that in fact two common raven lineages existed—one called “California” concentrated in the southwestern U.S. and the other called “Holarctic” found everywhere else.
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