Ryology and Vertebrate Phylogeny

Karyotypes and nuclear DNA contents of Polypteridae (Osteichthyes)

Calamoichthys calabaricus, Polypterus palmas, P. weeksii, P. delhezi and P. ornatipinnis have the same amount of DNA per erythrocyte nucleus. The karyotype of P. weeksii has 38 chromosomes and differs from the karyotypes of the other species, all with 36 chromosomes, by a Robertsonian chromosomal rearrangement. The karyotype condition is regarded as derived for vertebrates.

Chromosome polymorphism in the Italian newt, Triturus italicus

A chromosomal variation, changing shape and C-banding pattern of chromosome XII of Triturus italicus was detected among the offspring of two F1 hybrid families of T. italicus female x T. vulgaris meridionalis male. In both families a number of individuals appeared to have a metacentric instead of the expected subtelocentric chromosome XII of T. italicus.--Investigations in three well separated localities in the range of the species showed the polymorphism to have a wide distribution and to be part of a complex pattern involving at least two inversions and (presumably) deficiencies of large C-bands. At meiosis, the shape of bivalent XII, and the location and frequency of chiasmata in the bivalent varied with the karyomorph involved. It is suggested that large rearrangements may still play an important role in the karyological evolution of Triturus.