Gallus gallus, chicken

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Lavender phenotype in chicken

Vaez M, Follett SA, Bed'hom B, Gourichon D, Tixier-Boichard M, Burke T. A single point-mutation within the melanophilin gene causes the lavender plumage colour dilution phenotype in the chicken. BMC Genet. 2008 Jan 15;9:7.

The lavender phenotype in the chicken causes the dilution of both black (eumelanin) and red/brown (phaeomelanin) pigments. Defects in three genes involved in intracellular melanosomal transport, previously described in mammals, give rise to similar diluted pigmentation phenotypes as those seen in lavender chickens.

The lavender phenotype. Chickens expressing (a) wild type (LAV*N/LAV*N), and (b) lavender (LAV*L/LAV*L), phenotypes on an extended black (E*E) background.

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Pea-comb phenotype in chicken

Wright D, Boije H, Meadows JR, Bed'hom B, Gourichon D, Vieaud A, Tixier-Boichard M, Rubin CJ, Imsland F, Hallböök F, Andersson L. Copy number variation in intron 1 of SOX5 causes the Pea-comb phenotype in chickens. PLoS Genet. 2009 Jun;5(6):e1000512.

The featherless comb and wattles are defining features of the chicken. Pea-comb is a dominant mutation in chickens that drastically reduces the size of the comb and wattles. It is an adaptive trait in cold climates as it reduces heat loss and makes the chicken less susceptible to frost lesions. Whilst the Pea-comb allele was known to show a dominant inheritance and drastically reduce the size of both comb and wattles, the genetics underlying the mutation remained elusive. Chicken comb is primarily composed of collagen and hyaluronan, which are produced by chondrocytes. These cells are formed through the condensation and differentiation of mesenchyme cells during the chondrogenesis pathway, the early stages of which are regulated by SOX transcription factors. In this work authors pinpoint a massive amplification of a duplicated sequence in the first intron of SOX5 as causing the Pea-comb phenotype.

Wild-type and Pea-comb chickens. (A) Wild-type male, (B) wild-type female, (C) Pea-comb male and (D) Pea-comb female (Photo by David Gourichon).

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Yellow feet phenotype in chicken

Eriksson J, Larson G, Gunnarsson U, Bed'hom B, Tixier-Boichard M, Strömstedt L, Wright D, Jungerius A, Vereijken A, Randi E, Jensen P, Andersson L. Identification of the yellow skin gene reveals a hybrid origin of the domestic chicken. PLoS Genet. 2008 Feb 29;4(2)

This study convincingly demonstrates that while domestic chickens inherited the mitochondrial, and most of their nuclear genome from red junglefowl, the yellow skin allele originates from a species of junglefowl other than the red junglefowl, most likely from the grey junglefowl.

A. Map of South Asia onto which the ranges of four species of junglefowl are drawn.
B. European domestic chicken with yellow legs. Red, grey, blue, and green regions represent the respective ranges of red, grey, Ceylon, and green junglefowls.
C. Red junglefowl. D. Grey junglefowl. E. Ceylon junglefowl. F. Green junglefowl.
(Photo: Figures 1B: Björn Jacobsson; 1C: Erik Bongcam-Rudloff; 1D: John Corder, World Pheasant Association; 1E: Jean Howman, World Pheasant Association; 1F: Kenneth W Fink, World Pheasant Association).

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Naked neck phenotype in chicken

Mou C, Pitel F, Gourichon D, Vignoles F, Tzika A, Tato P, Yu L, Burt DW, Bed'hom B, Tixier-Boichard M, Painter KJ, Headon DJ. Cryptic patterning of avian skin confers a developmental facility for loss of neck feathering. PLoS Biol. 2011 Mar;9(3):e1001028.

Vertebrate skin is characterized by its patterned array of appendages, whether feathers, hairs, or scales. In avian skin the distribution of feathers occurs on two distinct spatial levels. Grouping of feathers within discrete tracts, with bare skin lying between the tracts, is termed the macropattern, while the smaller scale periodic spacing between individual feathers is referred to as the micropattern. The degree of integration between the patterning mechanisms that operate on these two scales during development and the mechanisms underlying the remarkable evolvability of skin macropatterns are unknown. A striking example of macropattern variation is the convergent loss of neck feathering in multiple species, a trait associated with heat tolerance in both wild and domestic birds. In chicken, a mutation called Naked neck is characterized by a reduction of body feathering and completely bare neck. Here we perform genetic fine mapping of the causative region and identify a large insertion associated with the Naked neck trait. A strong candidate gene in the critical interval, BMP12/GDF7, displays markedly elevated expression in Naked neck embryonic skin due to a cis-regulatory effect of the causative mutation. BMP family members inhibit embryonic feather formation by acting in a reaction-diffusion mechanism, and we find that selective production of retinoic acid by neck skin potentiates BMP signaling, making neck skin more sensitive than body skin to suppression of feather development. This selective production of retinoic acid by neck skin constitutes a cryptic pattern as its effects on feathering are not revealed until gross BMP levels are altered. This developmental modularity of neck and body skin allows simple quantitative changes in BMP levels to produce a sparsely feathered or bare neck while maintaining robust feather patterning on the body.

The Naked neck phenotype is caused by a cis-regulatory mutation that results in elevated BMP12 expression.
(A) Adult Na/Na. Feathers are absent on the neck and head, excepting the crown.
(B) E8.5 embryos hybridized with a β-catenin probe to mark the patterning field and feather primordia. Punctate expression of β-catenin in feather placodes is seen on the body but not the neck of the mutant. WT, wild type; Na/Na, Naked neck.
(C) E12.5 embryos showing limited lateral tract expansion (arrows) in Na/Na, reducing body feather coverage.
(D) Quantitative RT-PCR determination of BMP12 expression in body and neck skin of E7.5 and E8.5 wild type and Na/Na embryos.
(E,F) In situ hybridization detecting BMP12 in wild type and Na/Na embryos at (E) E7.5 and (F) E8.5. Wild type and mutant embryos were hybridized and photographed together. Na/Na embryos have elevated and diffuse expression of BMP12 in the skin.
(G) Sequence traces of PCR products from E8.5 Na/+. Genomic DNA PCR products display double peaks following a TA indel polymorphism in the BMP12 3′UTR. RT-PCR products from neck and body skin show a single trace throughout, indicating predominant expression of the Naked neck BMP12 allele, while both alleles are detected in RT-PCR products from other tissues.
(H) Schematic showing insertion of chromosome 1 sequences into chromosome 3 at the Naked neck locus. Chromosome coordinates, the Naked neck identical by descent segment, gene names, exons, untranslated regions, and non-coding elements conserved between chicken and human genomes, based on the ENSEMBL genome viewer, are indicated.

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Apparel and various household items with this design are available at GeoChemBio shop

Prints, posters, mugs and other drinkware as well as various bags and other household items with portraits of beautiful roosters are available at GeoChemBio shop

Mix and match to create your drinkware sets, to decorate your room or to make an original gift!

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References

• Bakst MR, Gupta SK, Akuffo V. Comparative development of the turkey and chicken embryo from cleavage through hypoblast formation. Poult Sci. 1997 Jan;76(1):83-90.
• Hamburger V, Hamilton HL. A series of normal stages in the development of the chick embryo. 1951. Dev Dyn. 1992 Dec;195(4):231-72.
• Coleman CM. Chicken embryo as a model for regenerative medicine. Birth Defects Res C Embryo Today. 2008 Sep;84(3):245-56.
• Rashidi H, Sottile V. The chick embryo: hatching a model for contemporary biomedical research. Bioessays. 2009 Apr;31(4):459-65.
• De Groef B, Grommen SV, Darras VM. The chicken embryo as a model for developmental endocrinology: development of the thyrotropic, corticotropic, and somatotropic axes. Mol Cell Endocrinol. 2008 Oct 10.
• Dawkins MS, Donnelly CA, Jones TA. Chicken welfare is influenced more by housing conditions than by stocking density. Nature. 2004 Jan 22;427(6972):342-4.
• Hester PY. Impact of science and management on the welfare of egg laying strains of hens. Poult Sci. 2005 May;84(5):687-96.
• Webster AB. Physiology and behavior of the hen during induced molt. Poult Sci. 2003 Jun;82(6):992-1002.
• Kanginakudru S et al. Genetic evidence from Indian red jungle fowl corroborates multiple domestication of modern day chicken. BMC Evol Biol. 2008 Jun 10;8:174.
• Burt DW. Emergence of the chicken as a model organism: implications for agriculture and biology. Poult Sci. 2007 Jul;86(7):1460-71.
• Axelsson E et al. Comparison of the chicken and turkey genomes reveals a higher rate of nucleotide divergence on microchromosomes than macrochromosomes. Genome Res. 2005 Jan;15(1):120-5. Epub 2004 Dec 8.
• Hamburger V, Hamilton HL. A series of normal stages in the development of the chick embryo. 1951. Dev Dyn. 1992 Dec;195(4):231-72.
• Eyal-Giladi H, Kochav S. From cleavage to primitive streak formation: a complementary normal table and a new look at the first stages of the development of the chick. I. General morphology. Dev Biol. 1976 Apr;49(2):321-37.
• Mason I. The avian embryo: an overview. Methods Mol Biol. 2008;461:223-30.
• Major topic "chickens": free full-text articles
• Animal Diversity Web: Gallus gallus
• Wikipedia: Chicken
• Mississippi State University: Poultry
• UNSW Embryology: Chicken Development Stages
• BEHAVIORAL AND MORPHOLOGICAL TRAITS ASSOCIATED WITH FERTILITY IN BROILER BREEDERS

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