The Journal of Heredity 1942:33(5):202-208
© 1942 The American Genetic Association 33:202-208
research-article |
A NEW TYPE OF AUTOSOMAL NAKEDNESS IN THE DOMESTIC FOWL
Alabama Agricultural Experiment Station Auburn
Abstract
A new type of nakedness occurring in the fowl is described. The character varies in expression from an extreme degree of nakedness, although not complete, to almost normal. The nudity is due wholly to the absence of pterylae in the areas of the body concerned. Where follicles are present, feathers develop normally. Down and semiplumes are absent in all apteria of the body.
The character is inherited as a simple autosomal dominant one. The evidence is in favor of the view that the mutation is recent, most likely having its origin in the immediate female parental germ cell. The data indicate that genetic modifiers of the character toward the normal have not developed in two generations of transmission of the character.
There is a degree of lethality associated with the character in hatched chicks, but the embryonic mortality is no greater than in normal chicks. The mortality is high at all stages of life, but particularly so during the first fifteen days, running as high as 57.9 per cent during this period. The lethal action of the gene is mitigated by feeding wet mash for certain periods of time; however, after discontinuance of wet mash mortality increases considerably.
The feed consumption of the mutant chicks on dry mash is about one-third to one-half less than that of normal chicks, while on wet mash it is increased; but it is still below normal.
The body weights of naked birds are also below those of normal ones at all weight periods except at hatching time; even at one year of age body weight is still below normal.
Evidence is presented to show that high death rate is not due to physical effects resulting from lack of feathers. While it is demonstrated that lethality is associated with a lowered feed consumption, this appears not to be the primary cause of death, but rather a consequence of some basic physiological disorder, possibly one concerned with digestion and assimilation.