Between 4 and 8 mitotic cells from each individual were analysed to determine the chromosome number. The best examples were photomicrographed at metaphase to document the chromosome number and morphology. A Nikon Eclipse 90i epi-fluorescence microscope equipped with a digital, cooled B/W CCD camera (VDS 1300B Vossku¨hler) was used with the appropriate filter (UV-2E/C excitation wavelength 340–380).