Origin & History: Described by Dunn, LC 1925 J Hered
16:127-134; held at Storrs since that time.
Breed: Single Comb White Leghorn
Symbol: Rp
Characteristics: Autosomal dominant
Description: Lacks most posterior vertebrae and the uropygial (oil) gland. Complete form lacks the 14 erect tail feathers of normal chickens; a few downward directed tail feathers are seen in the intermediate form. (J Genet 29:217-243, 1934) Complete and intermediate forms of rumplessness lack 1-2 vertebrae from the center of the synsacrum and the first 4 of the 6 vertebrae making up the pygostyle. The complete form lacks all 5 free caudal vertebrae; all 5 are present in the intermediate form but they are fused together irregularly. (J Hered 16:151-160, 1925; J Hered 19:453-465, 1928)