Lordosis, also known as swayback, low back or soft back, has been found to have a hereditary basis in Saddlebreds and a recessive mode of inheritance. The precise mutation has not yet been located, but researchers believe it to be somewhere on horse chromosome 20. Researching this condition may help more than just the Saddlebred breed as it may "serve as a model for investigating congenital skeletal deformities in horses and other species." Horses with lordosis are generally healthy and unaffected by the condition, and are eligible to compete in many divisions, but a swayback must be penalized as a fault at shows, in addition to other conformation flaws.