What is "brachyury"

n. (context biology English) The presence of an abnormally short tail in some animals as a result of a genetic mutation

Brachyury is a protein that in humans is encoded by the T gene. Brachyury is a transcription factor within the T-box complex of genes. It has been found in all bilaterian animals that have been screened, and is also present in the cnidaria.