Rapid evolution of cancer resistance in Tasmanian devil

Although cancer rarely acts as an infectious disease, in the past 20 years, a recently emerged transmissible cancer has appeared in the Tasmanian devil (Sarcophilus harrisii), and the cancer appears to be virtually 100% fatal. Devil facial tumor disease (DFTD) has swept across nearly the entire species’ range (the entire island of Tasmania, the island south of the Victoria State, Southeast Australia), resulting in localized decreases in population size of more than 90%. The overall decline in the species has been greater than 80% in less than 20 years.

As (evolutionarily) the largest remaining marsupial carnivore, Tasmanian devils are nocturnal, highly social, and (personally, I can attest to this) extremely aggressive toward one another. The frequency-dependent transmission of DFTD is spread by biting during social interaction (it’s so CUTE to watch). Despite epidemiological models that had predicted extinction before long, populations in long-diseased sites now persist. Authors [attached paper] report genomic evidence of a rapid, parallel (rare) evolutionary response to strong selection imposed by a wildlife disease. Authors identified two genomic regions––containing genes associated with human immune function or cancer risk that exhibit concordant signatures of selection across three populations. DFTD spreads between hosts by suppressing, and evading, the immune system. The data herein suggest that hosts are evolving immune-modulated resistance that could aid in species persistence in the face of an overwhelmingly serious disease.

Nature Commun  2o16; 7: 12684 [article]

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