The Tasmanian devil, a marsupial indigenous to the island of Tasmania (and formerly mainland Australia as well), experienced a population bottleneck in the late 1800s when farmers did their best to eradicate it. After it became a protected species, the population rebounded, but it is now experiencing a health crisis putting it at risk for disappearing again. Many current Tasmanian devil populations are plagued by a type of cancer called devil facial tumor disease, which occurs inside individual animals’ mouths. Afflicted Tasmanian devils can actually pass their cancer cells from one animal to another during mating rituals that include vicious biting around the mouth. Unlike the immune systems of other species, including humans, the Tasmanian devil’s immune system does not reject the passed cells as foreign or nonself (as we reject a liver transplant from an unmatched donor), but accepts them as if they were their own cells. Why would a population bottleneck result in the inability of one devil’s immune system to recognize another devil’s cells as foreign?
The Tasmanian devil, a marsupial indigenous to the island of Tasmania (and formerly mainland Australia as well), experienced a population bottleneck in the late 1800s when farmers did their best to eradicate it. After it became a protected species, the population rebounded, but it is now experiencing a health crisis putting it at risk for disappearing again. Many current Tasmanian devil populations are plagued by a type of cancer called devil facial tumor disease, which occurs inside individual animals’ mouths. Afflicted Tasmanian devils can actually pass their cancer cells from one animal to another during mating rituals that include vicious biting around the mouth. Unlike the immune systems of other species, including humans, the Tasmanian devil’s immune system does not reject the passed cells as foreign or nonself (as we reject a liver transplant from an unmatched donor), but accepts them as if they were their own cells. Why would a population bottleneck result in the inability of one devil’s immune system to recognize another devil’s cells as foreign?
Step by step
Solved in 2 steps
