Odd Antlers of the Animal Kingdom

Deer are undoubtedly one of the most iconic creatures of the North American animal kingdom, I mean they are the logo of four big hunting outfitting brands, two fairly large fitness brands, and three large hipster beard care brands. It is without a doubt that the iconic feature which attracts everyone to these herbivores is their elegant antlers.

While there is not a person alive who doesn't recognize these classic symbols, most people don't have the slightest clue how they work, I mean they are one of the fastest growing bones in the animal kingdom and they extend from a structure that is extremely similar to one that we as humans have, that being the skull, so how does that happen?

The answer is certainly shocking: the same genes which promote cell growth and suppress cancer cell development not only allow antlers to grow at the impressive weight they do but also maintain their shape. In deer antlers you see the same the genes which would promote tumors in humans create the rapid growth we associate with antlers but this growth is prevented from reaching a level that is unbeneficial to life for the deer by tumor suppressing genes. As Edward Davis says in the below article "...antlers [are] using essentially a controlled form of bone cancer growth".This means that during mitosis antler cells display bone cancer-like traits, growing and dividing at an abnormally fast rate. However, unlike bone cancer the growth of these cells is checked by tumor suppressor and growth genes. The tumor promoting genes are a fairly simpler concept, they simply promote cell division occurring at a higher rate but the truly amazing part of this is the genes which control cancer growth, which would be of clear interest of study to many(How Cancer Genes relate to Antler Growth ). 

Antlers are also a very promising field of study due to their extremely rare regenerative properties, sprouting in the spring and shedding in the winter, so this research could be of much interest towards therapies for bone diseases and injuries in human beings. The way scientists have attempted to deepen their understanding of this is by identifying the specific genes which lead this process. Through their research scientists at Stanford University have determined two genes which lead this process, uhrf1 and s100a10, although these two have entirely different purposes. The gene uhrf1 supports a higher rate of bone cell formation and s100a10 leads to a faster rate of mineralization. For those who are not familiar with what mineralization means in this context, more simply put, mineralization means the hardening of bone tissue, specifically due to the bone matrix becoming filled with calcium phosphate nanocrystals. This means that these two genes work together with uhrf1 growing the antlers and s100a10 shaping them into the classic shapes we associate with deer antlers.(Genetic research into Antler growth)
The problem that then arises is the same one that arises with any gene, what happens when one of these genes is turned off?

Now obviously any genes which have been turned off accidently in the DNA of a cell can be detrimental, these mutations can lead to any number of genetic disorders which can sometimes be incompatible with life. Luckily with deer antler growth the effect of either of the two pertinent genes being deactivated is not too severe as has been typically observed in the wild. As has been observed when the uhrf1 gene is non-functional deer will not have antler growth at an equitable rate and when the s100a10 gene is non-functional the rate and form of antler growth will not be suppressed and so will behave more like normal tumor cells. The s100a10 is clearly the more interesting of the two and can lead to a number of interesting yet sometimes worrying mutations.

 Image 4+5:Two deer with non-functional s100a10 genes (Link)

While these mutation are certainly interesting they are not incompatible with life for the deer and could even be beneficial to them in some scenarios. Despite these genes sometimes failing in nature, they could still prove vital to us as humans, because as mundane as deers may seem their iconic antlers might just hold the secret to preventing any other human from suffering from cancer, bone disease, or a broken bone ever again.

Zombie Deer Disease and Why We Should Fear it

This is the Zombie Apocalypse we should really be fearing because it is right at our doorstep. Now of course "Zombie Deer Disease" does not actually bring any deer back from the dead, they may just look like extras from The Walking Dead - Deer Edition. 

The proper name for this disease is Chronic Wasting Disease (CWD) and it is a progressive fatal degenerative neurological disease. Yeah, I know that all those words together are pretty freaking scary, however, you are in luck because so far it has only affected cervid populations. Cervids are the deer family, so moose, elk, mule deer, whitetail deer, reindeer, etc. and are found in all continents except Australia and Antarctica. CWD has been found in cervid populations in Canada, the United States, Norway, and South Korea (through imported deer). CWD is also a Transmissible Spongiform Encephalopathy or TSE, other TSEs are Bovine Spongiform Encephalopathy or Mad Cow disease, Scrapie, Creutzfeldt-Jakob Disease, and Fatal Familial Insomnia. TSEs are caused by abnormal proteins called prions.

A Healthy Stag (https://en.wikipedia.org/wiki/Deer#/media/File:Family_Cervidae_five_species.jpg)

Effects:
The effects of CWD are pretty scary they include holes eaten into the brain, drastic weight loss, lack of coordination and lack of fear of people (https://www.cdc.gov/prions/cwd/cwd-animals.html). Other than the obvious eating holes in the brain of the deer part there are also other reasons that this can wreak havoc on the populations. Discoordinated deer cannot protect themselves against predators like other deer can and they also do not realize that they should see humans as a threat. Also, deer with CWD by some reports die at a rate 3 times that of unaffected deer yearly. There are a few major problems that are hindering efforts to prevent CWD, first it has a really long incubation period of somewhere between 18 to 24 months and physiological symptoms do not show up until the very end. Also, it is really contagious among cervid populations and no one knows how to stop it yet. The main reason for the lack of prevention is it is not known how it is transmitted and even by depopulating any area it doesn't stop it from coming back in a totally new population later put in the area. Another reason that there is a problem is that not much can be done with the populations because no one knows how to stop it.

Deer suffering from CWD (https://www.nih.gov/news-events/news-releases/nih-study-finds-no-chronic-wasting-disease-transmissibility-macaques)

Research:

Luckily research has started to do with a few different aspects of CWD. At the University of Minnesota, they got $1.5 M to fund research into improving testing for CWD (https://www.vetmed.umn.edu/departments/veterinary-and-biomedical-sciences/spotlight/drs-pam-skinner-and-peter-larsen-aim-18m-funding-speed-chronic-wasting-disease-testing). Research was also done by the University of Wyoming to test the effects of CWD on cattle and it was found that cattle resist exposure to CWD which is good because it means that right now at least it will probably not transfer to cattle populations (http://www.uwyo.edu/uw/news/2018/05/long-term-research-shows-domestic-cattle-resist-oral-exposure-to-chronic-wasting-disease.html). The NIH also did a study to see if there was transmissibility of CWD to the primate Cynomolgus Macaque or Crab-eating Macaque for which they found no transmissibility which for humans is a good sign (https://jvi.asm.org/content/92/14/e00550-18).

Cynomolgus Macaque (https://www.nc3rs.org.uk/macaques/macaques/behaviour-and-communication/)

The Spread:
The best piece of news for humanity is actually that there is no piece of evidence for human risk yet. It has even been determined by some that most of the time a human can even eat deer meat infected with CWD. However, the threat of CWD is becoming more prevalently all the time with it now being in 21 states in the US.

Distribution of CWD in North America (https://www.usgs.gov/media/images/distribution-chronic-wasting-disease-north-america-0)

If you are interested, more information about CWD can be found at the CDC page of CWD (https://www.cdc.gov/prions/cwd/index.html) and at the CWD website (http://cwd-info.org/faq/).