The Journal of Heredity 1998:89(3)
© 1998 The American Genetic Association 89:264-266
Brief communication. Analysis of the inheritance of NOR size variants in brown trout (Salmo trutta)
Departamento di Biologia Fundamental, Area de Genetica, Universidad de Santiago de Compostela, 27002 Lugo, Spain *Corresponding author e-mail: paumarpo@lugo.usc.es.
The stability and the inheritance model of size variants of the main nucleolar organizer region (NOR) bearing chromosome pair 11 of brown trout (Salmo trutta) were studied by means of breeding experiments following a quantitative approach. The progenies (44 and 50 fishes) of two crosses between one sharp heteromorphic and one homomorphic parental for the NOR bearing chromosome pair were analyzed. NOR size distribution of the chromosomes from both progenies were mostly in accordance with a Mendelian model of inheritance. However, two chromosomes out of 188 analyzed showed an unexpected size, significantly different from parental chromosomes. This fact suggests NOR size changes across meiotic events in brown trout affecting long chromosome stretches.