Cytotaxonomic studies on Chilean galaxiid fishes. The karyotypes, C-bands, Ag-NORs and hybrids of Brachygalaxias gothei and B. bullocki (Osteichthyes: Galaxiidae)

Abstract

The cytogenetic analysis of Brachygalaxias gothei, B. bullocki and their hybrids showed differences in the number of biarmed and monoarmed chromosomes, as like as, in their c-banding patterns. The basic karyotype consists in 2n=40 with a FN=58 in B. gothei, and 66 in B. bullocki, and 2n=38+1 and FN=51 in the hybrids. B. bullocki presents a larger quantity of constitutive heterochromatin than B. gothei, and present a polymorphism in the location of one pair of NOR. The taxonomic status of B. gothei is discussed in relation of chromosome results and the hybrid sterility.