Date:October 21, 2015
Source:Central Ornithology Publication Office
How do birds evolve over generations? How do different bird populations diverge into new species? Ornithologists have been asking these questions since the days of Darwin, but rapid advances in genetic sequencing techniques in the last few years have brought answers more in reach than ever. A Review forthcoming inThe Auk: Ornithological Advancesdescribes some of the newest and most exciting developments in the field of "high-throughput sequencing," a collection of techniques for studying broad regions of a genome rather than individual genes.
High-throughput sequencing has been dropping in cost and complexity; once only available to large research consortiums, these methods are now feasible for smaller labs that were previously limited to working with individual genes or with mitochondrial DNA. "It's like going from seeing with a few light sensitive cells that can only detect the difference between night and day to a fully formed eye that can see all of the stars in the night sky," says David Toews of the Cornell Lab of Ornithology, the lead author of the Review.
Because high-throughput sequencing data looks at many genes instead of just a few, it makes it easier to identify very subtle genetic differences between populations, such as the genetics underlying small differences in plumage patterns between different subspecies of Wilson's Warbler. It can also provide a fresh look at the genetic changes that occur in "hybrid zones," where the ranges of closely related species overlap and members of the species breed freely with each other, such as where Black-capped and Carolina Chickadees meet in Pennsylvania. The process of one species splitting into two, such as what may be happening with the coastal and inland subspecies of Swainson's Thrush, is another intriguing area for study.