OMIA:002270-9031 : Ptilopody (Feathered shank), PITX1-related in Gallus gallus (chicken)

In other species: rock pigeon

Categories: Limbs / fins / digit / tail phene

Links to possible relevant human trait(s) and/or gene(s) in OMIM: 119800 (trait) , 186550 (trait) , 602149 (gene)

Mendelian trait/disorder: yes

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2020

Species-specific symbol: Pti-2

History: The first published report of this trait was by Hurst (1905). Other early reports were by Davenport (1906, 1909) and Punnett and Bailey (1918).

Inheritance: Up to three separate loci have been postulated to explain the inheritance of this ptilopody, with the trait being due to dominant alleles at two loci and a recessive allele at the third locus; hence the symbols Pti-1, Pti-2 and pti-3 (Somes, 1990; 1992). If more than one locus is confirmed, separate OMIA entries will be created for each locus. At present, the jury is still out. The preceding text was written before 2020. In 2020, the jury (in the form of Li et al. (2020) and Bortoluzzi et al. (2020)) returned its stunning verdict! Pti-1 is the gene TBX5 (OMIA 000839-9031), corresponding to the GGA15 QTL reported by Sun et al. (2015); and Pti-2 is the gene PITX1 (this entry), corresponding to the GGA13 region reported by Dorshorst et al. (2010) and to the GGA13 QTL reported by Sun et al. (2015).

Mapping: Dorshorst et al. (2010) tentatively mapped one ptilopody locus to 15.6Mb on chromosome GGA13. Sun et al. (2015): "Two QTL with 1% genome-wide significant level for feathered feet trait, one 9-cM/2.80-Mb (48.0-57.0/13.40-16.20 Mb) region on GGA13, and another 12-cM/1.45-Mb (41.0−53.0 cM/11.37−12.82 Mb) region on GGA15 were identified". Whole-genome sequencing of a full-sib family in which leg-feathering was segregating enabled Yang et al. (2019) to identify "a total of 24 promising candidate genes potentially affecting feathered-leg trait, i.e. FGF1, FGF4, FGF10, FGFR1, FRZB, WNT1, WNT3A, WNT11, PCDH1, PCDH10, PCDH19, SOX3, BMP2, NOTCH2, TGF-β2, DLX5, REPS2, SCN3B, TCF20, FGF3, FSTL1, WNT7B, ELOVL2 and FGF8." A GWAS conducted by Bortoluzzi et al. (2020) "revealed two significant signals on chromosome 13 and 15". Li et al. (2020) linkage mapped this trait to similar regions on chromosomes 13 and 15.

Molecular basis: In adjacent papers published on the same day in the same journal, Bortoluzzi et al. (2020) and Li et al. (2020) reported that the feathered variant of Pti-2 is a 17.7kb deletion upstream of PITX1. Intriguingly, this deletion is orthologous to the 44kb deletion upstream of PIX1 that gives rise to the same feathered trait in pigeons (see OMIA 002270-8932)

Associated gene:

Symbol Description Species Chr Location OMIA gene details page Other Links
PITX1 paired-like homeodomain 1 Gallus gallus 13 NC_052544.1 (15208701..15223907) PITX1 Homologene, Ensembl , NCBI gene


By default, variants are sorted chronologically by year of publication, to provide a historical perspective. Readers can re-sort on any column by clicking on the column header. Click it again to sort in a descending order. To create a multiple-field sort, hold down Shift while clicking on the second, third etc relevant column headers.

WARNING! Inclusion of a variant in this table does not automatically mean that it should be used for DNA testing. Anyone contemplating the use of any of these variants for DNA testing should examine critically the relevant evidence (especially in breeds other than the breed in which the variant was first described). If it is decided to proceed, the location and orientation of the variant sequence should be checked very carefully.

Since October 2021, OMIA includes a semiautomated lift-over pipeline to facilitate updates of genomic positions to a recent reference genome position. These changes to genomic positions are not always reflected in the ‘acknowledgements’ or ‘verbal description’ fields in this table.

OMIA Variant ID Breed(s) Variant Phenotype Gene Allele Type of Variant Source of Genetic Variant Reference Sequence Chr. g. or m. c. or n. p. Verbal Description EVA ID Year Published PubMed ID(s) Acknowledgements
1211 Feathered shanks PITX1 deletion, gross (>20) Naturally occurring variant GRCg6a 13 g.16089993_16107660del a 17.7kb deletion upstream of PITX1. 2020 32344431 32344429

Cite this entry

Nicholas, F. W., Tammen, I., & Sydney Informatics Hub. (2020). OMIA:002270-9031: Online Mendelian Inheritance in Animals (OMIA) [dataset].


Note: the references are listed in reverse chronological order (from the most recent year to the earliest year), and alphabetically by first author within a year.

2023 Cooper, R.L., Milinkovitch, M.C. :
Transient agonism of the sonic hedgehog pathway triggers a permanent transition of skin appendage fate in the chicken embryo. Sci Adv 9:eadg9619, 2023. Pubmed reference: 37196093. DOI: 10.1126/sciadv.adg9619.
Du, W., Yang, Z., Xiao, C., Liu, Y., Peng, J., Li, J., Li, F., Yang, X. :
Identification of genes involved in regulating the development of feathered feet in chicken embryo. Poult Sci 102:102837, 2023. Pubmed reference: 37390552. DOI: 10.1016/j.psj.2023.102837.
2020 Bortoluzzi, C., Megens, H.J., Bosse, M., Derks, M.F.L., Dibbits, B., Laport, K., Weigend, S., Groenen, M.A.M., Crooijmans, R.P.M.A. :
Parallel genetic origin of foot feathering in birds. Mol Biol Evol 37:2465-2476, 2020. Pubmed reference: 32344429. DOI: 10.1093/molbev/msaa092.
Li, J., Lee, M., Davis, B.W., Lamichhaney, S., Dorshorst, B.J., Siegel, P.B., Andersson, L. :
Mutations upstream of the TBX5 and PITX1 transcription factor genes are associated with feathered legs in the domestic chicken. Mol Biol Evol , 2020. Pubmed reference: 32344431. DOI: 10.1093/molbev/msaa093.
2019 Otecko, N.O., Ogali, I., Ng'ang'a, S.I., Mauki, D.H., Ogada, S., Moraa, G.K., Lichoti, J., Agwanda, B., Peng, M.S., Ommeh, S.C., Zhang, Y.P. :
Phenotypic and morphometric differentiation of indigenous chickens from Kenya and other tropical countries augments perspectives for genetic resource improvement and conservation. Poult Sci 98:2747-2755, 2019. Pubmed reference: 30850827. DOI: 10.3382/ps/pez097.
Yang, S., Shi, Z., Ou, X., Liu, G. :
Whole-genome resequencing reveals genetic indels of feathered-leg traits in domestic chickens. J Genet 98, 2019. Pubmed reference: 31204699.
2016 Domyan, E.T., Kronenberg, Z., Infante, C.R., Vickrey, A.I., Stringham, S.A., Bruders, R., Guernsey, M.W., Park, S., Payne, J., Beckstead, R.B., Kardon, G., Menke, D.B., Yandell, M., Shapiro, M.D. :
Molecular shifts in limb identity underlie development of feathered feet in two domestic avian species. Elife 5:e12115, 2016. Pubmed reference: 26977633. DOI: 10.7554/eLife.12115.
2010 Dorshorst, B., Okimoto, R., Ashwell, C. :
Genomic regions associated with dermal hyperpigmentation, polydactyly and other morphological traits in the Silkie chicken. J Hered 101:339-50, 2010. Pubmed reference: 20064842. DOI: 10.1093/jhered/esp120.
2003 Bartels, T. :
Variations in the morphology, distribution, and arrangement of feathers in domesticated birds. J Exp Zool B Mol Dev Evol 298:91-108, 2003. Pubmed reference: 12949771. DOI: 10.1002/jez.b.28.
Sawyer, R.H., Knapp, L.W. :
Avian skin development and the evolutionary origin of feathers. J Exp Zool B Mol Dev Evol 298:57-72, 2003. Pubmed reference: 12949769. DOI: 10.1002/jez.b.26.
1993 Shoffner, R.N., Otis, J.S., Garwood, V.A. :
Association of dominant marker traits and metric traits in chickens. Poultry Science 72:1405-1410, 1993. Pubmed reference: 8378215.
1992 Somes, R.G. :
Identifying the Ptilopody (Feathered Shank) Loci of the Chicken Journal of Heredity 83:230-234, 1992. Pubmed reference: 1624770.
1990 Somes, R.G. Jr :
Mutations and major variants of plumage and skin in chickens. In "Poultry Breeding and Genetics" (ed. R.D. Crawford), Elsevier, Amsterdam; Chapter 6 :169-208, 1990.
1971 Goetinck, P.F. :
Genetic tests on the association of brachydactyly and ptilopody in fowl. J Hered 62:28-30, 1971. Pubmed reference: 5094713.
1967 Goetinck, P.F. :
Tissue interactions in the development of ptilopody and brachydactyly in the chick embryo. J Exp Zool 165:293-300, 1967. Pubmed reference: 4292956. DOI: 10.1002/jez.1401650213.
1954 Saeki, Y. :
Inheritance of shank feathering (ptilopody) in silky fowl Bulletin of the National Institute of Agricultural Science, Japan, Series G :43-47, 1954.
1949 Warren, DC. :
Linkage relations of autosomal factors in the fowl. Genetics 34:333-50, 1949. Pubmed reference: 17247319.
1938 Fisher, R.A. :
Dominance in poultry - Feathered feet, rose comb, internal pigment and pile. Proceedings of the Royal Society, Series B: Biological Sciences 125:25-48, 1938.
1933 Warren, D.C. :
Nine independently inherited autosomal factors in the domestic fowl. Genetics 18:68-81, 1933. Pubmed reference: 17246678.
1927 Dunn, L.C., Jull, M.A. :
On the inheritance of some characters of the Silky fowl Journal of Genetics 19:27-63, 1927.
1926 Serebrovsky, A.S. :
The genetics of the domestic fowl. II. The genetics of leg feathering. Memoirs of the Anikowo Genetical Station, 1926. [Abstracted by L. C. Dunn from the translation of B. F. Glessing] Journal of Heredity 20:111-118, 1926.
1918 Punnett, R.C., Bailey, P.G. :
Genetic studies in poultry. I. Inheritance of leg feathering Journal of Genetics 7:203-213, 1918.
1909 Davenport, C.B. :
Inheritance of characteristics in the domestic fowl Washington, D.C.: Carnegie Institution of Washington. Publication 121 :1-100, 1909.
1906 Davenport, C.B. :
"Inheritance in poultry". Washington, D.C.: Carnegie Institution of Washington. Publication 52. :1-136, 1906. DOI: 10.5962/bhl.title.29926.
1905 Hurst, C.C. :
Experiments with poultry. Reports to the Evolution Committee of the Royal Society 2:131-154, 1905.

Edit History

  • Created by Frank Nicholas on 24 May 2020
  • Changed by Frank Nicholas on 03 Jun 2020
  • Changed by Frank Nicholas on 09 Jun 2020