La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	[Is the immutabilis-gene transmission in Mute Swans (Cygnus olor) subjected to selection?]
Auteurs :	Erwin Rudolf Scherner, Auteur
Type de document :	Article
Dans :	Vogelwarte (40(3) November, 2000)
Article en page(s) :	242-245
Langues:	Allemand
Résumé :	Two phases, termed "normal" and immutabilis ("Polish Swan") respectively, are known in Cygnus olor. The differences between them refer to down coat, juvenile plumage and unfeathered skin parts (e. g., feet). The dimorphism is controlled by two sex-linked alleles with dominance of "normal". Dark-footed pairs belong to the genotypes Aa (heterozygous male) and A0 (hemizygous female) if their progeny contain at least one "Polish" bird (A0 female). The segregation ratios observed in a sample of such families (n = 142) agree with those expected from the HARDY-WEINBERG and MENDEL formulae. This reveals evidence of the so-called mechanical sex-ratio (1 : 1) among cygnets prior to fledging.

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