Elephant Genes and Protection From Cancer

Very interesting research has revealed why elephants—at least in captivity—have a much lower cancer rate than us. Elephants live about as long as humans yet have far more cells. Like all cells, elephant ones could potentially become cancerous. It would seem that elephants should have a higher rate of cancer than humans instead of a lower one because of their larger size and their greater number of cells. Researchers have discovered two interesting genetic reasons that might explain why this isn’t the case.

An estimated 17 percent of humans worldwide die from cancer, but less than five percent of captive elephants—who also live for about 70 years, and have about 100 times as many potentially cancerous cells as humans—die from the disease. Quote from the University of Chicago Medical Center via the phys.org news service

An African elephant

ajoheyho, CC0 public domain license

The P53 Gene

A gene known as P53 seems to be important in protecting elephants from cancer. It’s sometimes referred to as a master tumour suppressor gene. We have the gene, too. The difference is that we have only one copy of the gene (on paired chromosomes) while elephants have twenty. The activated gene causes the destruction of cells with DNA damage. This damage often precedes the conversion of the cell to a cancerous one. The extra genes in elephants likely enables their body to destroy more potentially dangerous cells.

A Resurrected Pseudogene

The second genetic benefit in elephants is linked to something called a pseudogene, which is sometimes referred to as a dead gene. When genes are copied, a mistake is sometimes made and non-functional copies are produced. While the researchers were studying P53 genes in elephant cells, they encountered an active form of the LI6 gene, which was a surprise. The gene was inactivated long ago in the elephant’s evolutionary history and was though to be still “dead”.

The full name of the LI6 gene is the leukaemia inhibitory factor 6 gene. Like other genes, it codes for proteins. In this case, the protein molecules travel to the mitochondria of cells with damaged DNA. As a result, the mitochondria of the cell are damaged and the cell dies. Mitochondria generate most of the energy required by the cell and are vital organelles. Studies in elephant cells suggest that the P53 gene activates the LI6 gene.

A young African elephant

Mariamichelle, CC0 public domain license

Manipulating the Human Genome

More studies are needed in order to understand the function and interactions of the elephant genes. The exploration might not only be fascinating biologically but also useful in understanding and treating cancer in humans. Researchers are making progress in treating cancer and have made significant discoveries recently, but the disease is still serious. Although we are smaller than elephants, we have many cells and many chances for DNA errors and damage to occur.  The actual number of cells in the human body is unknown.

The short answer is that the body of an average man contains around 30 to 40 trillion cells. The long answer is that scientists do not yet know the exact number. Plus, it depends on whether or not you include the bacteria that are present in and on our bodies. Quote from Yelia Hewings-Martin, Medical News Today

Humans have 20,000 to 25,000 genes. Gene activation and activity are complex processes. Trying to manipulate the human genome without understanding what we’re doing could have unintended consequences. Still, the research in elephant cells may help us learn about useful genes or chemicals in human cells and perhaps lead to beneficial discoveries that don't require the manipulation of genes. Understanding the human body and developing better treatments for diseases are wonderful goals.

References

Resisting cancer by waking a zombie gene from the phys.org news service
Cancer rarely strikes elephants from National Geographic
Number of cells in the human body from Medical News Today