Finding ancient secrets in Songbirds
Evolutionary genomicist Bohao Fang, who spearheaded the research as a postdoctoral fellow, is pictured holding a house finch. Photo by Kelsie Lopez/Courtesy of Bohao Fang
In a recent study published in Current Biology, postdoctoral fellow Bohao Fang and Professor Scott Edwards reveal that endogenous retroviruses — genetic sequences derived from ancient viruses — are abundant in the DNA of modern songbirds. But they remain concealed in “germline-restricted chromosomes” (GRCs), or DNA carried only in the ovaries and testes.
GRCs have been found in a diverse array of species across the bird family tree, and many biologists suspect they are universal among all passerines. Indeed, a separate team recently posted a study showing that GRCs were likely present in all 6,700 passerine species and probably originated before songbirds branched off from their avian cousins.
The authors characterized the GRC as a “hidden but potentially important driver of genome innovation in birds.” For example, Edwards theorized that material from the GRC might somehow jump to or influence other parts of the genome and thereby seed new adaptations.
The study, featured in the FAS Current, is the first to show these mysterious genetic sequences at work in songbirds.