An international team of geneticists has discovered that the Tasmanian devils transmissible cancer, DFTD, has five other forms.
The generic term for Tasmanian devils’ cancer is DFTD. Previously, two variations of it were discovered: DFT1 and DFT2.
The proliferation of DFT1 and the second variation of DFT2 has put the Tasmanian devils on the brink of extinction. The disease began to spread among small marsupial predators around the mid-1990s, wiping out up to 95% of their population over the past 20 years.
Four years ago, Elizabeth Murchison, a professor at the University of Cambridge in the UK, and her colleagues discovered that there are actually two DFTD cancers, DFT1 and DFT2, spreading in parallel. This became the starting point to study the varieties of the disease in more detail: it was hypothesized that there are more than two of them.
To answer these questions, biologists collected and analyzed the genomes of over 600 samples of DFT1 tumors extracted from devils’ bodies between 2003 and 2018. As a result, it turned out that there are not two but five types of DFT1 cancer at once. Two of them, dubbed D and E, managed to spread only among a small number of animals, after which they became extinct, but three others, A, B, and C, continue to spread in different regions of Tasmania. The last three turned out to be the most deadly: these types of times killed up to 99% of Tasmanian devils.
Further study of the varieties of the disease, the team hopes, will help understand how to protect surviving marsupial predators from infection with DFTD and develop effective treatment methods.