Chromosome Alteration and Development of Tumors. XXIV

Hypo-pentaploid Chromosome Constitution of a Spontaneous Tumor Developed in the Oceanian Type Black Rat, with Particular Reference to Centromeric Fission

Abstract

Karyotype analysis was made in a tumor (fibrosarcoma) developed in an Oceanian type black rat. The tumor was characterized by a hypo-pentaploid stemline. The chromosome constitution consists of varying elements such as pentasomic, tetrasomic, hexasomic, trisomic and disomic. Centromeric fission was especially noted in the large metacentric M2, playing an important role in the chromosome alteration.