In all organisms, somatic cells are diploloid, and sexual cells are typically haploid. The cells that are diploid have two homologous copies of two chromosomes inherited through two parental. The majority of mammals are diploid, with the exception of some rats. But, studies that have disproved that there is polyploidy among mammals have been conducted. Polyploidy is a condition where cells possess chromosomes which are more than diploid number of chromosomes. The majority of organisms that reproduce through mitosis have 2n DNA chromosomes, forming diploid cells.