Abstract
The chromosomes were studied in several kittens (Felis domestica), 2 or 3 days in age, having different coat colors based on cells from kidney and heart cultures. Cells squashed from testicular tissues of an adult black cat were also used as material (Table 1). Twelve metaphasic cells from 5 kittens were analysed with camera lucida drawings as well as with photomicrographs (Figs. 4, 5, 7 and 8). They were found to possess the diploid chromosome-number of 38. Referring to the size, shape and the position of the centromere, 38 chromosomes were tentatively classified into 6 groups of autosomes and a pair of sex chromosomes. Karyotype analyses revealed that the chromosomes were fairly the same in all kittens under study in their morphology, except for an XY-mechanism in males, and XX-mechanism in females. The X-element with a submedian centromere was found to correspond in size to the 14th autosomal pair. The Y-chromosome having a subterminal centromere corresponded in size to the smallest metacentric autosomes.
A detailed chromosome study was made on the somatic cells from a probably tabby tortoiseshell male cat (Figs. 6 and 10) in which were found 38 chromosomes of a normal male complement. The origin of male tortoiseshell cats were discussed in relation to the chromosomal findings.
