Elephants and other large animals are rarely ill cancer. This gave scientists the idea that they possess some protective mechanism that protects them from this disease. That’s just what the mechanism was not clear until recently. A new study for the first time lifted the veil of secrecy and allowed to find the answer to a science question. It turned out that the protection of elephants from cancer lies in their unique genome.
Multicellular animals are designed so that their cells go through numerous cycles of growth and division. For each division the new cell receives the entire genome of the original, but in the end there begin to be copied and various “genetic error” and the mutations, which ultimately leads to the development of cancer. Previously, scientists assumed that the secret lies in the size of mammals: times more cells, and mutations start to occur considerably later than animals of smaller size. But the reality was not so. And the risk of cancer is hardly related to the size.
In fact, elephants and other large mammals have developed mechanisms of protection against cancer. In 2015, Joshua okay, shiffman of the Medical University of Utah and Carlo Maley of Arizona state University led a research which should answer this important question. It turned out that the elephant genome contains 20 additional duplicates-suppressor gene p53, that suppresses the development of tumors. But defense mechanism against this deadly disease is not solely limited to, additional copies of genes.
A new study under the guidance of genetics Vincent Lynch of the University of Chicago completed the discovery made two years ago. It turned out that the genome of elephants and some other animals also contains duplicates of the LIF-encoding gene factor inhibiting leukemia, as well as participating in the fertility, reproduction and stimulating the growth of embryonic cells. To exclude the relationship between these two deviations, the scientist has studied the cell and came to the conclusion that LIF genes have certain disorders that prevent them to perform their functions properly, but they have something in common with the genes of p53.
To find out why elephants need damaged genes, the researchers subjected the DNA of cells intentional damage. The result of the cell not to destroy itself, as it usually happens in the process of apoptosis (programmed cell death). So it became clear that the LIF duplicate genes represent a kind of “pseudogene” — the old, mutated and useless copies of genes that in some mysterious way survived in the genome. Scientists came to the conclusion that the modern elephants, these pseudogene inherited from their historical ancestors, including the mammoths that lived on Earth millions of years ago.
In modern elephants ancient pseudogene evolved into a viable genes LIF6. And they, in turn, simply does not accumulate harmful mutations that lead eventually to cancer, simply brakwa cancer cells in the early stages. Thus, LIF6 inhibits cancer, and additional copies of the gene to kill unwanted cells in the case if they suddenly aktiviziruyutsya. And the gene p53 controls the operation of LIF, thereby causing the entire protective system in balance. Part of the duplicates of these genes are responsible for the animals ‘ fertility and reproduction, and the remainder at the same time fighting cancer cells. Such a division of scientists was very surprised.
Now scientists are seriously thinking that protects from cancer of the whales, because they had no extra copies of the p53 gene. It is likely that their disease protects from a completely different genetic mechanism, but the solution to this mystery, they still have a lot to work with. The researchers believe that the solution to such mysteries of nature opens the door for them to be able to defeat cancer in the case of people. However, while no one can say exactly how and when it happens.
Scientists have discovered why elephants don’t get cancer
Sergey Grey