A New Chromosome Number in the Indian Spiny Mouse, Mus platythrix

The Indian spiny mouse, Mus platythrix , has a characteristic karyotype consisting of 26 acrocentric chromosomes with a few larger autosomes derived the karyotype of this species from that of the house mouse, M. musculus , by proposing tandem fusions of several pairs of the autosomes. He suggested that chromosome evolution might have occurred sequentially by the fusion. Aswathanarayana and Manjunatha have discovered a female of this species with 2n = 25 with a fused metacentric chromosome. The authors discovered a male with a reduced chromosome number of 24, characterized by all acrocentrics.