Tails you lose for lizards

lizard tail stock image

The natural ability of lizards to drop and then regrow their tails is a neat evolutionary trick that allows them to avoid predators and remain alive.

But new research from the University of Tasmania – published recently in Biology Letters – reveals the hidden cost of dropping a tail to a lizard’s overall wellbeing.

According to University of Tasmania School of Natural Sciences PhD candidate Luisa Fitzpatrick, the reason behind the biological cost lies in ‘telomeres’ – caps located on the ends of the DNA found in all plants and animals, which prevent errors in recombination.

Every time a cell divides, telomeres are partially eroded, Ms Fitzpatrick explained.

In humans, telomeres generally get shorter as they age, and it is when they become critically short that age-related symptoms such as grey hair and wrinkles begin to occur.

But the telomeres of lizards are an entirely different beast to that of humans and other mammals because reptiles can repair their telomeres throughout their lifetime.

“I looked at lizards that lost their tails and regrew them over two months to see if the telomere length changes during regeneration,” Ms Fitzpatrick said.

“We expected telomeres to get shorter as regrowing the tail is associated with a lot of cell division, but in fact, we saw no change in telomere length in lizards regrowing tails.

“Lizards with their tails intact, by contrast, lengthened their telomeres during the two months. So the lizards are trading off investing in cell maintenance by instead investing in regrowing the tail.

“This tells us that regrowing the tail comes at a cost to lizards outside the obvious investment of energy in growth. It also costs them in terms of their overall quality.”

Ms Fitzpatrick said despite the obvious short-term benefits to lizards of dropping a tail it did come at the cost of compromised telomere repair.

Source: UTAS

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