Flatworms could hold key to immortality Flatworms, known as planarian worms, have long fascinated scientists because they have an extraordinary ability to regenerate. A planarian worm split lengthways or crossways will regenerate into two separate living worms. The researchers found that flatworms can continuously maintain the length of a crucial part of their DNA, known as telomeres, during regeneration. Dr Aboobaker's team studied two types of planarian - those that reproduce sexually, like humans, and those that reproduce asexually by simply dividing in two. Both types appear to regenerate indefinitely by growing new muscles, skin, guts and even entire brains again and again, but the asexual ones also renew their stocks of a key enzyme which may mean they can be immortal, the study said. Scientists know that one of the key factors associated with ageing cells is telomere length. Telomeres are sections of DNA that cap the ends of chromosomes, protecting them from damage and the loss of cell functions linked to ageing. Shorter telomeres are thought to be an indicator of faster ageing.