Are They or Aren’t They? Only the Genome Knows for Sure

Photo of a Greater Sage Grouse (BLM Photo)

If it looks like a greater sage-grouse, and acts like a greater sage-grouse…is it? Sage-grouse have been split into two species (greater and Gunnison sage-grouse) based on genetic differences as well as morphology (physical characteristics) and behavior. Within the greater sage-grouse range, however, is a population along the border between California and Nevada (the bi-state population) that has been shown to be genetically unique, such that some experts question whether this might be a distinct species. But unlike Gunnison Sage-grouse, the bi-state birds are behaviorally and morphologically similar to other greater sage-grouse. The genetic data used under previous genetics methods to characterize these divisions were generated from a small number of genetic markers. When USGS researchers re-examined those divisions using a genomic approach, with its many thousands more markers spread throughout the genome, they found that the bi-state population, though still genetically different from the rest of the greater sage-grouse population in some ways, is not different in the DNA markers that are under selection—markers that code for things like behavior and morphology. This is a much clearer distinction that explains why the Gunnison is truly a unique species, and the bi-state population is not. These genomic methods provide much more comprehensive answers to what have been, up to now, problematic questions. USGS geneticist Sara Oyler-McCance presented on this study, "Re-examining genetic variation in sage-grouse using genomic methods," at The Wildlife Society's annual meeting November 2011 in Kona, Hawaii. Read the full report at Evaluation of the genetic distinctiveness of Greater Sage-grouse in the Bi-State Planning Area.

For more information contact: Sara Oyler-McCance