Genome Ploidy

Abstract

Traditionally, ploidy (euploidy) has been defined in eukaryotic cells. A cell containing only one homologue of each chromosome is haploid. Cells containing two homologues of each chromosome are diploid; three homologues, triploid, and so on. By this convention, most bacteria in general, and E. coli in particular, contain one homologue of their single chromosome and are considered to be haploid. However, when the differences in the cell cycles of eukaryotes and prokaryotes are considered, this distinction becomes less clear.