A phylokaryotypic evaluation of the genus Tursiops (family Delphinidae)
There is considerable controversy over the number and distribution of species in the genus Tursiops (Odontoceti: Delphinidae). In an attempt to correlate genetic data with possible species delineation, this study investigates the presence of chromosomal variants between the North Atlantic bottle nose dolphin, Tursiops truncatus, and the North Pacific bottle nose dolphin, T. gilli. Blood 2 samples were obtained from oceanaria in the United States. Location of capture was correlated with
... lated with karyotype to compare chromosome morphology with geographic range. The samples of whole blood were added to culture media and incubated for four days, then treated with Colcemid to collect a number of cells undergoing mitosis. Metaphase cells were harvested and mounted on glass slides. For standard karyotyping the slides were stained with Giemsa. A C-banding technique was used to examine heterochromatin distribution by pretreatment of the slides with an alkaline solution and then staining with Giemsa. Cells from each animal were examined by microscope and photographed. Karyotypes were constructed from the photographic prints, and chromosome morphology and banding patterns were compared. There was considerable variation in C-banding among the Tursiops examined. There were no clear distinctions between the Atlantic and Pacific forms, nor between coastal versus offshore captive sites. The results indicated that Tursiops populations exhibit a great deal of chromosomal polymorphism in the form of C-band heterochromatin variability.