The karyotype of Franciscana dolphin (Pontoporia blainvillei)

Despite the recent increase in studies on franciscana dolphin (Pontoporia blainvillei) molecular biology, there has been no published karyotype information, as opportunities for sampling live individuals are very rare. In the present study, the diploid number of the species was established from corneal cell cultures of 2 newborn male franciscanas live stranded (2n = 44). From the comparison of the chromosomal number to the cetacean karyotype phylogeny, we suggest that the most parsimonious hypothesis is that the ancestral character state in the group is the diploid number of 42, with an extra chromosome pair appearing independently twice during cetacean evolution, once in the suborder Odontoceti and once in the suborder Mysticeti. This information on chromosomal number may be useful to future genetic mapping projects of the species.