 However this is only observed in fast growing cultures, whereas cultures grown in synthetic minimal media are not polyploid.The archaeon "Halobacterium salinarium" is polyploid and, like "Deinococcus radiodurans", is highly resistant to X-ray irradiation and desiccation, conditions that induce DNA double-strand breaks.Although chromosomes are shattered into many fragments, complete chromosomes can be regenerated by making use of overlapping fragments.