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In the early days of EleFacts, we shared the fascinating truth of elephant’s mutating genes that prevent them from getting cancer. To refresh your memory, elephants possess what is lovingly referred to as a “zombie” gene. In human and animal bodies, cells are constantly mutating and, in some cases, our DNA repair genes can catch these mutations and stop them. Cancer, however, prevents these genes from doing their job. Research has shown that elephants have a gene that almost always causes cancer cells to completely die off, preventing the damaged DNA from developing into cancer. This augmented cancer resistance has most likely evolved throughout history. Cancer is not a cause of death that is often recorded in elephants, although we must remember that there’s a severe lack of total and accurate necropsies that are completed as well as a lack of database recording in many cases. 

New data has emerged in the last few weeks that provides a bit more insight into how this zombie gene came to be. Research suggests that the absence of testicular descent in elephants may have driven the development of multiple anti-cancer genes, with the intention of protection for their temperature-sensitive sperm production. In mammals, healthy sperm is produced based on the reproductive organs being several degrees cooler than normal body temperature, which is helped by the descent of the testicles as a mammal reaches maturity. Elephants, however, lack the genes responsible for this descent, resulting in their testicles remaining inside their bodies even in mature bulls, subjecting them to elevated temperatures. 

So how are these two related? Researchers are arguing that protecting offspring is a big source of evolutionary pressure. Mutations, like the zombie gene, that allow for healthier and longer-living offspring are more likely to be passed through generations. The thought is that this gene was originally developed and intended not to fight cancer, but to protect sperm production; the result of that just happens to also decrease the chance of an elephant getting cancer.

This fascinating research is not just a reminder of the medical mysteries that remain in the animal world, but a sign that we may be able to learn more about our own human bodies with the help of species that deserve our care and protection.

Photo of Rana