Somes R G
Department of Nutritional Sciences, University of Connecticut, Storrs 06269-4017.
J Hered. 1991 Mar-Apr;82(2):169-72. doi: 10.1093/oxfordjournals.jhered.a111054.
Allelism at the duplex comb locus was studied by means of crosses between the Sicilian Buttercup and La Flèche breeds of chickens and two single combed breeds. The horn V-shaped duplex comb of the La Flèche was shown to be inherited as an incomplete dominant when crossed with single comb birds, and it exhibited complete penetrance and a strong expression of duplex. The buttercup duplex comb of the Sicilian Buttercup in similar crosses was also shown to be inherited as an incompletely dominant trait, but with this type comb penetrance was reduced by 32% in females and its expression of duplex was greatly reduced when compared with the La Flèche. When the duplex comb types were crossed to each other, the V-shaped comb showed complete dominance over the buttercup comb. It is proposed that there are at least three alleles at the duplex locus: D (v-type) greater than Dc (buttercup type) greater than d+ (non-duplex type). The most dominant allele (Dv) causes both doubling of the comb and suppression of its tissue mass, while the less dominant allele (Dc) only causes doubling of the comb.
通过西西里毛茛鸡和弗莱谢鸡品种与两个单冠品种的鸡进行杂交，研究了双冠位点的等位基因情况。当弗莱谢鸡的角形V形双冠与单冠鸡杂交时，显示出作为不完全显性遗传，并且它表现出完全的外显率和强烈的双冠表达。在类似杂交中，西西里毛茛鸡的毛茛形双冠也显示为不完全显性性状，但这种类型的鸡冠在雌性中外显率降低了32%，与弗莱谢鸡相比，其双冠的表达大大降低。当两种双冠类型相互杂交时，V形冠对毛茛形冠表现出完全显性。有人提出，在双冠位点至少有三个等位基因：D（V型）大于Dc（毛茛型）大于d+（非双冠型）。最显性的等位基因（Dv）导致鸡冠加倍并抑制其组织质量，而较不显性的等位基因（Dc）仅导致鸡冠加倍。
