Reindeer, specifically Rudolph and his herd, have unique adaptations that could potentially be used to develop treatments for human diseases. Although it is commonly believed that reindeer can fly due to the popular holiday poem "Twas the Night Before Christmas," this is not true.
However, reindeer have various abilities that allow them to thrive in the Arctic, such as the ability to change the color of their eyes, see in ultraviolet light, regulate their body clocks, produce vitamin D even with limited sunlight, and grow large antlers quickly. These adaptations make reindeer well-suited to their environment and could potentially be studied to understand how to improve human health.
Furthermore, the unique adaptations of reindeer could benefit human health in various ways. For example, studying reindeer could lead to the development of treatments for jet lag, insomnia, cancer, and even the ability to regrow limbs. Recent research has shed light on the genetic basis of reindeer's unique traits, which could potentially be used to develop new medical treatments for humans. Reindeer are found in the Arctic regions of Alaska, Siberia, and Greenland, with the largest group being the Taimyr herd in Siberia.
Ruminant Genome Project
In June 2021, the Ruminant Genome Project published the first results of its study comparing the DNA of reindeer with that of other cud-chewing animals. The study identified numerous mutations unique to reindeer and related to their adaptations to the Arctic environment. These findings were surprising and demonstrated the significant genetic adaptations that reindeer have developed to survive in their environment, according to Zhipeng Li at the Chinese Academy of Agricultural Sciences.
According to Rasmus Heller at the University of Copenhagen, many of the same genes involved in certain human processes are also involved in similar processes in reindeer. One example is the biological clock, which helps regulate daily rhythms of activity and inactivity in humans and most other animals based on light and dark. Reindeer also have a biological clock but can override it when necessary. For example, during the long days of the Arctic summer, reindeer will forage almost constantly to gain as much weight as possible. In the dark winter months, their metabolic levels decrease, and they only have short periods of activity that do not follow a 24-hour pattern. These adaptations allow reindeer to survive in their harsh environment.
Reindeer are not the only polar animals that can override their biological clock. Emperor penguins and rock ptarmigan, a grouse, also have this ability. This ability is necessary for animals living in the Arctic because of the unusual light conditions in the region. These changes in light can affect the secretion of hormones and other physiological processes, so Arctic animals need genetic adaptations to cope with these conditions.
Reindeers' Unique Gene Variation
Reindeer, also known as caribou in North America, are the only deer species that have been domesticated by humans, with about half of the population being domesticated. Reindeer come in various sizes, with males of the smallest subspecies weighing around 90 kilograms on the Norwegian islands of Svalbard, while stags in Finland can weigh up to 250 kilograms. Reindeer can thrive in harsh environments, such as extreme cold and limited food in the winter, as well as prolonged periods of daylight and darkness.
The Ruminant Genome Project has revealed that reindeer have unique versions of genes that regulate circadian rhythms, specifically a mutated form of the protein Per2 that prevents another protein crucial for this regular cycle from binding to it. This malfunction in the biological clock is essential for reindeer to survive in their environment.
The discovery of these gene variants in reindeer could potentially be used to help humans overcome jet lag. This condition occurs when a person travels to a different time zone and has to readjust to the light/dark cycle. Disruptions to the circadian rhythm are also thought to contribute to mood disorders such as depression, and studying the biological mechanisms that allow reindeer to override their circadian rhythms could provide insight into treating these conditions.
Additionally, the gene variants involved in insomnia in humans could be compared with the genes of reindeer to understand better how people's circadian rhythm is affected. Another impressive ability of reindeer is their ability to regrow antlers every year. Both male and female reindeer can do this, and the antlers can contain up to 10 kilograms of bone and blood vessels and grow up to 2.5 centimeters per day. Deer antlers are one of the only mammalian organs, aside from the placenta, that can be completely regenerated. The process by which reindeer can regrow their antlers so quickly and efficiently is not yet fully understood.
Potential Help for Humans
Research published earlier this year suggests that the genes activated in cells that will become antlers are also activated in cancer cells. This connection between tissue regeneration and cancer growth highlights the potential for studying reindeer in the development of cancer treatments. However, reindeer are five times less likely to develop cancer than other mammals because they have evolved highly efficient mechanisms for suppressing tumors that control cancer pathways. This ability makes reindeer an interesting subject for researchers looking for new ways to prevent or treat cancer in humans.
Growing antlers requires a significant amount of calcium, which can be difficult for reindeer to obtain in their environment. To absorb calcium from food, mammals need vitamin D, which is produced through sunlight on the skin. In the Arctic, where there is very little sunlight for half the year, reindeer need to maximize their calcium uptake and vitamin D production. The Ruminant Genome Project found that reindeer have a highly efficient system for producing vitamin D, which allows them to overcome this challenge. This system is more efficient than the one that humans have for producing vitamin D.
Studying the process by which reindeer grow antlers could potentially help researchers develop treatments for bone diseases such as osteoporosis or bone cancer in humans. The way that antlers are attached to the skull has already inspired the design of a new type of bone-anchored prosthesis for people with missing limbs. While the idea of flying reindeer and red noses may be charming, the real adaptations that reindeer have developed to thrive in their environment are just as impressive and have the potential to be used to benefit human health in a variety of ways.
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