Sizing chromosomes and megaplasmids in haloarchaea

Chromosomal size is conserved in the genera of haloarchaea while plasmid size and composition vary among different strains from the same species and also in the same strain. Pulsed-field gel electrophoresis of different species and strains of haloarchaeal genera indicates the presence of one chromosome between 1.8 to 3 Mb in all members. At least one, but generally many plasmids between 90 and 680 kb are present in supercoiled or linear forms in the haloarchaea.