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Biomedical subjects

U K Abbott

Publications and source records attributed to U K Abbott.

41 records · Page 3Linked to original sources
PubMedDate not supplied

Genetics of scoliosis in chickens.

The genetics of an inherited form of scoliosis in chickens was studied to estimate the number of genes involved, whether they are autosomal or sex-linked, their degree of dominance and penetrance, and the heritability of this trait in this population. Expression of scoliosis and in the progeny was analyzed by radiographs of birds 12 weeks of age or older. Crosses between an inbred line selected for scoliosis expression (incidence of scoliosis - 89 percent) and a highly inbred line displaying normal spinal development provided data for genetic analyses. The incidence of expression of scoliotic parent line implicates three major autosomal, recessive genes. The significantly higher incidence of severe scoliosis found in the homogametic male sex is ascribed to a sex-influenced, on the scoliosis trait rather than to sex-linkage. Variation of expression observed in the scoliotic line is attributed to incomplete penetrance of the major genes, additive effects of minor modifying genes, and primarily to environmental effects. Because of the similarities in the expression of this disease in chickens and humans, the inheritance pattern determined for chickens may provide useful insights into that operating for so-called adolescent idiopathic scoliosis in humans.

Animals↗
PubMedDate not supplied

A new chondrodystrophy mutation in Japanese quail (Coturnix japonica).

A second form of hereditary chondrodystrophy (ch-2) has been discovered in a selected line of Japanese quail, Coturnix japonica. This form of chondrodystrophy is autosomal and recessive, characterized by an overall shortening and bending of the long bones of the wings and legs, slight dwarfing of the trunk, bulging of the eyes, flattening of the head, and a parrot beak. The shortened long bones vary in regard to the amount of bending from nearly straight to bends of up to 90 degrees in the midshaft region. In severe cases, the bend is evident as a protuberance of the skin. Affected embryos usually survive the 18-day incubation period. Several have hatched, but most survived no longer than 4 days after hatching. Only one female has survived long enough to lay eggs. Testcrosses indicated that this mutation is not allelic to micromelia.

Animals↗
PubMedDate not supplied

Effects of the sex-linked dwarf gene (dw) on the expression of the muscular dystrophy gene (am) in chicken.

The sex-linked dwarf gene (dw) was introduced into companion muscular dystrophic (am) and nondystrophic (Am+) New Hampshire chicken lines to investigate influences of the dwarf gene on breast muscle weights, muscle fiber area, and the histological expression of muscular dystrophy. Dystrophic and nondystrophic chickens within dwarf or nondwarf genotypes were similar in body and carcass weights. Pectoralis and supracoracoideus muscle weights (as a percentage of adjusted carcass weight) were similar in nondystrophic dwarf and nondwarf males and females. In addition, pectoralis weight was similar in dystrophic dwarf males and dystrophic nondwarf males and females. However, pectoralis weight was significantly smaller in dystrophic dwarf females than in dystrophic nondwarf females, whereas supracoracoideus weight was significantly larger in dystrophic dwarf males than in dystrophic nondwarf males. Supracoracoideus weight was similar in dystrophic dwarf males and females and dystrophic nondwarf females. Pectoralis muscle fiber area was influenced by sex and by dwarf and dystrophy genotype. Muscle fiber area was larger in females than in males, smaller in dwarfs than in nondwarfs, and smaller in dystrophic than in nondystrophic muscles. Muscle fiber degeneration and adipose infiltration was more extensive in dystrophic than in nondystrophic females and males, and it was more advanced in dwarfs than in nondwarfs. Excessive acetylcholinesterase staining patterns were characteristic of dystrophic muscle in both dwarf and nondwarf genotypes. Nondystrophic and dystrophic dwarf male and female chickens are comparable substitutes for nondwarfs as biomedical models with respect to pectoralis histology, acetylcholinesterase staining pattern, and pectoralis muscle hypertrophy.

Acetylcholinesterase↗