For the last twenty or so years, a transmissible facial cancer has all but decimated the Tasmanian devil population. There have been localized population declines of more than 90% and an overall species decline of more than 80% within the last two decades. Some models were even predicting extinction.
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While they are still listed as endangered, Andrew Storfer from Washington State University and his team believe they will be okay, however. In an interview with Research Gate, they revealed that there are two genomic regions that have genes related to immune function and cancer risks that have developed across the population.
The cancer is almost 100% fatal to those who are infected because it grows on the face, impairing breathing and eating. The disease itself is spread through biting, and Tasmanian devils bite each other quite frequently. Since it is caused by an infectious cell line, it is directly transmitted.
The study looked at the genomes of 294 Tasmanian devils and looked at their genes before the cancer arrived and after a few generations of the cancer. They found that there was evolution in two small sections of the genome that contained seven genes. They found that within a few generations, "five of the seven genes were associated with immune response and cancer in other mammals, including humans."
They used "RAD-seq" to restrict the enzymes and cut the genome into small pieces. They were then sequenced on a "next-generation" DNA sequence, aligned, and the differences were identified. There were over 90,000 versions, taking up approximately 20% of the Tasmanian devil genome. The team had to look for changes in frequency in the samples.
In the end, they found that the immunity already existed within the Tasmanian devil and increased in frequency due to natural selection.
Of course, there are still some worries within the community because there has been quite a decline. Still, this is a sign of hope.