(Nn) Naked Neck pigeon genetics

A Romanian Naked Neck Tumbler showing Nn//Nn. Photo: Jim Gifford.
A Romanian Naked Neck Tumbler showing Nn//Nn. Photo: Jim Gifford.

Naked Neck (symbol Nn) is an unusual trait found in several European breeds – primarily the Romanian Naked Neck Tumbler and the Spanish Naked Neck. This gene exhibits itself with an apparent absence of feathers on the neck of the pigeon.

Inheritance

Nn is an incomplete dominant gene. This means that in a homozygous state (Nn//Nn), the neck will be completely bare of feathers. In a heterozygous state (Nn//+) it will only exhibit partially and the bird’s neck will have patchy feathering.

Mechanism

Naked necked pigeons do in fact have working feather follicles on their necks, and each year with the moult they will begin to grow new neck feathers. However, at some point during the growth of the feather it will stop growing, atrophy and fall off.

Naked necks are found almost exclusively in Ash-red pigeons (and therefore not on blue/black or brown birds). Another peculiarity is that white feathers on the neck will survive the process and grow normally. This has led to the hypothesis that the naked neck is caused by a toxin produced during feather development.

Ash-red pigeons are coloured with pheomelanin (in contrast with the eumelanin of our blue/black pigeons). The thought is that the pigment-producing cells, when producing pheomelanin in neck feathers, also produce some form of toxin that inhibits the growth of the feather. This would explain why Nn is exhibited almost exclusively in Ash-red pigeon and why white feathers are spared.

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