In other species: chicken , , budgerigar , ringneck dove

Mendelian trait/disorder: yes

Mode of inheritance: Autosomal Recessive

Considered a defect: no

Key variant known: yes

Year key variant first reported: 2013

Cross-species summary: Also called feather-crested head.

Species-specific description: As summarised by Vickrey et al. (2015), "the head crest of domestic pigeons is a recessive phenotype characterized by reversed polarity of the neck and occipital feathers, causing the feathers to grow in a cranial rather than caudal direction".

Molecular basis: Shapiro et al. (2013) reported that "All 8 crested birds were homozygous for a T nucleotide at scaffold 612, position 596613 (hereafter, “cr” allele), while uncrested birds were heterozygous (n=3) or homozygous (n=30, including the uncrested outgroup C. rupestris) for the putatively ancestral C nucleotide (“+” allele). These results were consistent with the known simple recessive architecture of the trait. . . . we genotyped an additional 61 crested birds from 22 breeds, and 69 uncrested birds from 57 breeds, and found a perfect association between cr/cr genotype and the crest phenotype". As reported by Vickrey et al. (2016), the SNP results in "a single amino acid substitution (Arg758Cys) in the active site of the kinase domain of Ephrin receptor B2".

Associated gene: