Some observations on high cavernous nostrils in the chicken.

Area of Science:

• Animal Genetics
• Poultry Science
• Morphological Genetics

Background:

• Nostril shape in chicken breeds varies, with cavernous nostrils associated with V-shaped duplex combs and slit-type nostrils in others.
• The Sicilian Buttercup breed, featuring a buttercup-type duplex comb, exhibits slit-type nostrils.

Purpose of the Study:

• To investigate the genetic basis of cavernous nostrils in chickens.
• To determine the inheritance pattern of nostril morphology in relation to comb type alleles.

Main Methods:

• Crossbreeding experiments involving Sicilian Buttercup, La Flèche, and single comb chicken breeds.
• Analysis of nostril morphology and comb type in offspring to infer genetic linkage.

Main Results:

• Cavernous nostrils are a pleiotropic effect of the Dv allele at the duplex comb locus.
• The Dv allele is inherited recessively when crossed with the wild type (d+).
• The buttercup allele (Dc) modifies the expression of the Dv allele, leading to dominant inheritance of mutant nostrils in specific combinations.

Conclusions:

• Cavernous nostrils are proposed to be a pleiotropic effect of the comb-size-reducing function of the Dv allele.
• The genetic interaction between Dv and Dc alleles influences nostril morphology in chickens.