Cytogenetic Study in Salmo irideus and S. trutta fario

Abstract

S. trideus showed some variations of chromosome number around the mode at 2n = 60, as a result of increasing and decreasing the number of chromosomal arms (NF) probably through the meiotic non-disjunction. S. t. fario possessed a well individualized chromosome complement, with 2n = 80 and NF = 104. It differs from the complement of the original species, S. trutta, in the number of chromosome arms. The increase of the NF is caused by the presence of 1-2 supplementary pairs of meta- or submetacentric chromosomes, probably produced through duplication processes.