title: Cytogenetic and phenotypic effects of a chromosomal rearrangement involving the Z-chromosome and micro-chromosome in the chicken.
abstract: Measurements demonstrated that the Z-chromosome was truly metacentric. Forty-six percent of one arm of a female's Z-chromosome had been translocated to a microchromosome (Z-micro) by irradiation of semen. The bread was 23 crossover units distal to the late feathering (K) locus. The barring (B) locus on the non-broken arm assorted almost independently of the Z-micro segment. Semen from eight sons of this Z-micro female was used to inseminate 98 dwarf (dw) broiler-type females. From karyotypes of 147 male and 149 female progeny, we identified 69 males heterozygous and 79 females hemizygous for Z-micro. Body weight of 43 males heterozygous for Z-micro was significantly greater than that of 45 normal Z paternal half-brothers at all ages from 2 to 24 weeks. In contrast, body weight of 57 Z-micro females compared with their 56 normal Z paternal half-sisters was depressed significantly at 2, 4, and 6 weeks but not significantly at 8, 12, 16, and 24 weeks of age. Age at first egg was retarded 8 days and egg production over a 153 day test period was reduced 19.6%, primarily due to a reduction of egg laying sequence from 2.7 to 2.1 days in the Z-micro females.
mesh_terms: D000818:Animals; D001835:Body Weight; D002645:Chickens / Q000254:growth & development / Q000502:physiology; D002869:Chromosome Aberrations; D002875:Chromosomes; D003434:Crossing Over, Genetic; D004531:Eggs; D005241:Feathers; D005260:Female; D005298:Fertility; D005808:Genes, Recessive; D006579:Heterozygote; D006720:Homozygote; D008297:Male; D010641:Phenotype; D012744:Sex Ratio; D014178:Translocation, Genetic