Diploid-Triploid Chimerism in 3 Tortoiseshell Cats

A cytogenetical investigation of 1 intersex and 2 male tortoiseshcll cats revealed diploid-triploid chimerism in all 3 animals. The intersex cat, which had 1 hypoplastic testis, abnormal external genitalia and a female genital tract, had the chromosome constitution 2n = 38 XX/ 3n = 57 XXY. One of the male cats also had the chromosome constitution 2n = 38 XX/ 3n = 57 XXY and was probably infertile. The second male cat appeared to have the chromosome constitution 2n = 38 XY/ 3n = 57 XXY. This animal was probably fertile as all stages of spermatogenesis were seen in sections of testis. Previous reports of cytogenetical investigations of male tortoiseshcll cats are briefly summarised.