Araucanas have a most interesting and controversial history, having originated in a remote area of Chile ruled by fierce Araucana Indians who resisted European domination until the 1880’s. The distinctive traits of blue egg, tufts and rumplessness originally were found in two distinct breeds from this region. The first breed, named “Collonocas/Kolloncas”, laid blue eggs and were rumpless. The second breed, called “Quetros/Ketros”, had unusual tufts, but were tailed and laid brown eggs.
Where did these unusual traits come from?
Eggshell pigments have been associated with protoporphyrin and biliverdin. Protoporphyrin is responsible for brown eggs, while the bile pigment biliverdin is responsible for blue or green eggs. White eggs contain very low concentrations of one or both pigments, or non at all. The accumulation of biliverdin in the eggshell is an autosomal dominant trait called oocyan, leading to blue/green shelled eggs. This trait has been known in Mapuche fowl and Dongxiang. The Mapuche fowl includes the rumpless blue/green egg laying ‘kollonca’ and the tailed ear-tufted ‘ketro” which lays mostly brown eggs. Crossing of these breeds, as stated above, gave origin to the tufted rumpless Araucana. Recently Wang Zhepeng and other scientists from the College of Animal Science and Technology of China identified an endogenous avian retroviral (EAV-HP) insertion in Chinese Dongxiang chicken associated with the over-expression of a solute carrier, SLCO1B3. EAV-HP is likely responsible for the oocyan phenotype. Quantitative real-time PCR analysis of European oocyan chicken indicates over-expression of the SLCO1B3 gene in the shell gland and oviduct. Evidence suggests that the EAV-HP insertion is a de novo mutation in domestic chickens. The results also support the parallel post-domestication, integration of an endogenous retrovirus leading to the oocyan phenotype in South America and Asian chickens. This provides no support for an introduction of the phenotype to South America from Asia or vice versa. The close genomic proximity of the EAV-HP integration to SLCO1B3, its unique presence in oocyan chickens and the tissue-specific over-expression of the solute carrier, known to transport bile salts such as biliverdin, strongly supports the retroviral insertion as the causative mutation of the oocyan phenotype in Mapuche fowl and their modern descendants. It is suspected that the over-expression in the shell gland of SLCO1B3, for which biliverdin is a substrate, might increase the accumulation of biliverdin in the shell gland during shell matrix formation, giving rise to blue eggs.
Wragg D, Mwacharo JM, Alcalde JA, Wang C, Han JL, et al. (2013) Endogenous Retrovirus EAV-HP Linked to Blue Egg Phenotype in Mapuche Fowl. PLOS ONE 8(8): e71393
The first written evidence of the existence of blue eggs in Chile was in 1883, and by 1914 they were commonly found throughout South and Central America.
The rumpless breed called Walle Kiki, or Persian Rumpless, was introduced by the Dutch during the colonial period and became widespread. The Araucana Indians preferred this trait since they believed that lack of tail feathers made it harder for predators to catch them. This trait quickly became common in their flocks.
The tufts gene is the most mysterious of all. Presumably there was a mutation in a gene that resulted in these ornamental tufts. Left to natural selection the trait would soon die out because of its negative affects on the developing embryo. The gene mutation is lethal if two copies are present, and the embryo dies in shell. Even one copy of the gene is associated with about 20% mortality. Therefore, the Araucana Indians must have decided that it was a desirable trait and consciously propagated it. Many of the original tufted birds had a distinctive “laughing crow”, although that is seldom heard in modern Araucanas. Perhaps there was some religious or ceremonial aspect involved in their maintenance.
The development of the modern Araucana breed begins with the great Chilean breeder, Dr. Ruben Bustros. As a young man in the Chilean army, he encountered the Araucana Indians in remote areas and observed their unique types of chickens during the 1880’s. He returned later and obtained some of the Quetros and Collonocas stock. Crossing these two breeds, over many years he developed tufted, rumpless birds that laid blue eggs, the first Araucanas. He was visited in 1914 by Professor Salvador Castello Carreras of Spain, who introduced them at the World Poultry Congress in 1918.
Attempts to import Araucana stock into the United States over the years met with great difficulties. The original Quetros and Collonocas breeds were especially hard to obtain because the Araucana Indians had been defeated and disbanded and their birds mixed with other breeds. Also, evidently Dr. Bustros’s flock was not maintained. However, a few breeders managed to get birds with the required traits of tufts, blue egg and rumplessness. But these birds were fairly pathetic mixes of a number of other breeds and much effort was required for improvement. However, there was no common goal among these few dedicated breeders until the 1960’s when Red Cox started an Araucana breeders group. His untimely death set things back, and it wasn’t until the late 1970’s that the Araucana was recognized as an official breed.