Ulisse Aldrovandi, Monstrorum Historia, Bologna, Nicola Tebaldini, 1642, page 562 (cropped)

Creeper chickens are characterised by abnormally short legs, so short that the body is carried a few centimetres from the ground. This

chondrodystrophy Chondrodystrophy (literally, "cartilage maldevelopment") refers to a skeletal disorder caused by one of myriad genetic mutations that can affect the development of cartilage. As a very general term, it is only used in the medical literature when ...

(dwarfism) is caused by a recessive lethal allele, ''Cp''. A number of breeds display the characteristic, among them the

Chabo The Japanese Bantam or Chabo ( ja, 矮鶏) is a Japanese breed of ornamental chicken. It is a true bantam breed, meaning that it has no large fowl counterpart. It characterised by very short legs (the result of hereditary chondrodystrophy) and ...

and Jitokku breeds of Japan, the Courte-pattes of France, the Krüper of Germany, the Luttehøns of Denmark, and the

Scots Dumpy The Scots Dumpy is a traditional Scottish breed of chicken. It is characterised by very short legs, so short that the body is a few centimetres from the ground; as in other breeds of creeper chicken, this chondrodystrophy is caused by a rece ...

History

Creeper chickens have been known and described since

Renaissance The Renaissance ( , ) , from , with the same meanings. is a period in European history marking the transition from the Middle Ages to modernity and covering the 15th and 16th centuries, characterized by an effort to revive and surpass ideas ...

times at least. They have been called by many names, among them bakies, brevicrews, corlaighs, crawlers, creepers, creepies, dumpfries, dumpies and jumpers. In his ''

The Variation of Animals and Plants Under Domestication ''The Variation of Animals and Plants under Domestication'' is a book by Charles Darwin that was first published in January 1868. A large proportion of the book contains detailed information on the domestication of animals and plants but it al ...

'' of 1868,

Charles Darwin Charles Robert Darwin ( ; 12 February 1809 – 19 April 1882) was an English naturalist, geologist, and biologist, widely known for his contributions to evolutionary biology. His proposition that all species of life have descended fr ...

writes that creeper chickens were among the types described in a Chinese encyclopaedia compiled from earlier sources and published in 1596. The creeper was described and illustrated in the ''Monstrorum Historia'' of the Bolognese naturalist

Ulisse Aldrovandi Ulisse Aldrovandi (11 September 1522 – 4 May 1605) was an Italian naturalist, the moving force behind Bologna's botanical garden, one of the first in Europe. Carl Linnaeus and the comte de Buffon reckoned him the father of natural history st ...

(1522–1605), published posthumously in 1642 with text by Bartolomeo Ambrosini. The creeper gene was described by Ira Eugene Cutler in 1925, and confirmed by Walter Landauer and L.C. Dunn in 1930. The symbol ''Cp'' was assigned to it by

Frederick Hutt Prof Frederick Bruce Hutt HFRSE (29 August 1897 – 6 September 1991) was a Canadian zoologist and geneticist in the 20th century. His book Animal Genetics has 31 published editions from 1964 to 1981 and is translated into six languages. He mad ...

in 1933. It was shown to be present in the

by Landauer in 1942, in the Jitokko by S. Okamoto in the same year, and in the Gan-Dori and Miyaji-Dori by Tohru Shibuya in 1972.

Biology

The short legs of creeper chickens are the result of

autosomal dominant In genetics, dominance is the phenomenon of one variant (allele) of a gene on a chromosome masking or overriding the effect of a different variant of the same gene on the other copy of the chromosome. The first variant is termed dominant and t ...

transmission of a

lethal allele Lethal alleles (also referred to as lethal genes or lethals) are alleles that cause the death of the organism that carries them. They are usually a result of mutations in genes that are essential for growth or development. Lethal alleles may be rec ...

, ''Cp''. Affected birds are

heterozygous Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mo ...

(''Cp''/+) for the gene;

homozygotes Zygosity (the noun, zygote, is from the Greek "yoked," from "yoke") () is the degree to which both copies of a chromosome or gene have the same genetic sequence. In other words, it is the degree of similarity of the alleles in an organism. Mo ...

(''Cp''/''Cp'') die at the

embryo An embryo is an initial stage of development of a multicellular organism. In organisms that reproduce sexually, embryonic development is the part of the life cycle that begins just after fertilization of the female egg cell by the male spe ...

stage. The ''Cp'' trait is linked closely to the gene for the rose comb, ''MNR2''. Shortening of the leg bones is also observed in

Indian Game The Indian Game is a British breed of game chicken, now reared either for meat or show. It originated in the early nineteenth century in the counties of Cornwall and Devon in south-west England. It is a heavy, muscular bird with an unusually ...

, and some birds carry a lethal allele. It is quite different to that of the creeper; Hutt assigned it the symbol ''Cl''.

References

{{reflist, 45em, refs= Walter Landauer (1942)
Studies on the Creeper Fowl. XIV. The Japanese Bantam Fowl
''The American Naturalist''. 76 (764): 308–317. {{doi, 10.1086/281045. {{subscription required. Greg Davies (December 2016)
About the Creeper Gene
''Aviculture Europe''. 12 (5), article 10. Accessed August 2022. Keiji Kinoshita, Takayuki Suzuki, Manabu Koike, Chizuko Nishida, Aki Koike, Mitsuo Nunome, Takeo Uemura, Kenji Ichiyanagi, Yoichi Matsuda (2020)
Combined deletions of ''IHH'' and ''NHEJ1'' cause chondrodystrophy and embryonic lethality in the Creeper chicken
''Communications Biology''. 3: article 144. {{doi, 10.1038/s42003-020-0870-z. Ira Eugene Cutler (October 1925)
Reptilian Fowls: A Study in Atavistic Heredity
''Journal of Heredity''. 16 (10): 353–356. {{doi, 10.1093/oxfordjournals.jhered.a102511. {{subscription required. Scots Dumpy / United Kingdom (Chicken)
Domestic Animal Diversity Information System of the Food and Agriculture Organization of the United Nations. Accessed December 2019. Charles Darwin (1868)
''The Variation of Animals and Plants Under Domestication''
London: John Murray. F.B. Hutt (1949)
''Genetics of the Fowl''
New York: McGraw-Hill Book Company. F.B. Hutt (1933)
Genetics of the Fowl. II. a Four-Gene Autosomal Linkage Group
''Genetics''. 18 (1): 82–94. {{doi, 10.1093/genetics/18.1.82. Janet Vorwald Dohner (2001). ''The Encyclopedia of Historic and Endangered Livestock and Poultry Breeds''. New Haven, Connecticut; London: Yale University Press. {{isbn, 0300088809. Walter Landauer, L.C. Dunn (1930)
Studies on the creeper fowl
''Journal of Genetics''. 23 (3): 397–413. Tohru Shibuya, Yoshihisa Fujio, Kyoji Kondo (1972)
Studies on the action of Creeper gene in Japanese chicken
''The Japanese Journal of Genetics''. 47 (1): 23–32. {{doi, 10.1266/jjg.47.23. Ulisse Aldrovandi (1642)
''Ulyssis Aldrovandi patricii Bononiensis Monstrorum historia: cum Paralipomenis historiae omnium animalium ... ''
(in Latin). Bononiae: Typis Nicolai Tebaldini. Aviculture Animal genes