Chromosome polymorphism in Salmo trutta morpha lacustris from Poland, Wdzydze Lake population: Variation in the short arm length of chromosome eleven

Abstract

A population of Salmo trutta m. lacustris from Lake Wdzydze was karyotyped using C-banding and fluorochrome staining techniques. The chromosome number was 2n = 80, and the chromosome arm number (NF) was 100-102. Variation in the size of the short arm of chromosome pair eleven was observed: the presence of heterochromatin on this arm was confirmed by C-banding and DAPI staining. Chromomycin A3 and silver stainings revealed the presence of nucleolar organizer region (NOR) on this arm. Additional CMA3-positive regions were observed on two acrocentric chromosomes. The polymorphism of chromosome pair eleven observed in Salmo trutta m. lacustris probably resulted from deletions or multiplications of heterochromatin connected to NOR. The karyotype and observed polymorphism of the NOR-bearing chromosome pair was the same as observed in other ecological forms of Salmo trutta.