Chromosomes of the Fox

Microchromosomes in the American Red Fox, <i>Vulpes fulva</i>

“…Metaphase spreads of female, number four ( as a result of cell rupture at the time of slide preparation (Gustavsson andSundt 1965, Moore andElder 1965), the results of this study suggest that this may not be the cause of the variation in cell count. Consistent with the suggestion of Gustavsson and Sundt (1967) that the microchromosomes are heterochromatic, the results of our preliminary auto radiographic study showed the single microchromosome of the cub to be late labeling.…”

“…In the two male foxes these elements ranged in numbers from 3 to 7 with a modal number of 5. (Gustavsson andSundt 1965, Moore andElder 1965). Analyses of spreads prepared in this manner failed to reveal any apparent difference in the number or arrangement of the chromosome comple ment; consistent association of the minute elements with macrochromosomes or with each other, however, was not observed.…”

“…Since it had been suggested that the variable number of chromosomes in the fox might be caused by a loss of microchromosomes during slide preparation and was, therefore, artifactual and due to cell rupture (Gustavsson 1964, Moore andElder 1965), cell cultures were established in large Leighton tubes containing standard microscope slides. At a time when the cells were rapidly dividing, colchicine was added to the cultures to accumulate metaphase figures; subsequently, the monolayers were treated with hypotonic saline and then fixed by flooding the culture tubes with fixative.…”

“…Gustavsson and Sundt (1965) found different modal numbers for each of four red foxes from two different commercial fox farms; in an earlier study Gustavsson (1964) reported 38 chromosomes for the red fox. Moore and Elder (1965), on the other hand, failed to find any variation in chromosome number in the animals they studied and reported a diploid count of 38 chromosomes, although they noted that frequently a smaller number was found and attributed this dis crepancy to the "loss" of one or more microchromosomes in the process of preparation.…”

B chromosomes in populations of mammals

“…Compared to plants and insects, in which Bs were noticed at the beginning of the 20 th century and for which lists of species possessing them are long, chromosome investigations in mammals are of recent origin due to technical difficulty. Since B chromosomes are present in (Hayman and Martin, 1965) and the red fox, Vulpes vulpes (Moore and Elder, 1965). Later on studies disclosed that Bs are mostly outspread among rodents (42 species, F 2.1 %, i.e.…”