Atavism: The Secrets of the Past and the Key to the Future

Atavism: The Secrets of the Past and the Key to the Future

Meaning the return of ancestral features to an organism, this word has only recently appeared in my vocabulary. I came across it whilst reading Robert Winston’s ‘The Human Mind’, in which he was describing Cesare Lombroso’s work. The sentence read ‘He compared these with the skulls of non-human primates and came to the view that criminals were ‘throwbacks’ – the consequence of atavism.’ Now, being a fifteen year old, secondary school student, I haven’t studied evolution in that depth let alone Atavism itself, so understandably I was not aware of what it was. Therefore I took it upon myself to research the term in order to gain a better understanding of what Winston was referring to.

Upon researching Atavism, I found that I was finding it increasingly interesting and that, not only had I learnt a new word but also that, Atavism had lead me on to reading articles about topics such as Phylogenetic ideas, Ontogeny and The Recapitulation Theories. All being rather interesting topics, I decided I would write about Atavism. I understand that I will probably not be able to give the most intellectual response; however it was something I wanted to do.

Living in a social community where being different is now considered a positive thing, I was not surprised to see the flashes of pig-like-tails and hair-covered-humans when I searched Atavism. When in modern day, you can be famous for almost anything, it wasn't the first time I had seen images of this nature, however I wasn't seeing these images purely for entertainment.  As I previously said, I wanted to learn about what Atavism was. Consequently, I began to see these images as not the odd deformities that appear on the pages of the Guinness Book of World Records, but instead as what they truly were, an anomaly in human evolution.  Atavism is a backtrack, a reverse, an anti – progression, an oddity. However for the exact definition, the Oxford English Dictionary states the following:

•         The reappearance of a characteristic in an organism after several generations of absence, usually caused by the chance recombination of genes.
•         An individual or a part that exhibits Atavism. Also called a throwback.
•        The return of a trait or recurrence of previous behaviour after a period of absence.

I personally think that this depicts Atavism perfectly. It tells you with a limited amount of words exactly what it is. However the only disadvantage of definitions is that they never tell you why. Yes, it briefly mentions the fact that Atavism is usually caused by the chance recombination of genes however it doesn’t say why these genes, that haven’t been used in so long, suddenly reappear. Even though there will always be an element of them within the organism, surely with these genes being so old, and ‘faint’, there would be a considerably larger amount of dominant genes, in which case this ancient gene would be discarded.

Yet it seems as though this is not the case, as we obviously do have these ‘Ancient Genes’ coming through. In Homo sapiens, it is most commonly present as an extra nipple or a tail like feature around the bottom of the back. Although absurd, they do make some form of sense. These were both features that an ancestor of modern man once had. When it comes down to it, without these features, we wouldn't be what we are today because somewhere along the line we will have had to evolve and adapt to different situations in which we may have not needed a tail anymore. However depending on the time in which this change occurred will have affected the rest of man’s evolution, therefore it is a factor that leads us to where we are today. Just like in hundreds of thousands of years’ time, our modern day human, will just be another drawn out figure in a long line of ape like beings on an evolutionary graph.

Now this idea of the evolutionary graph is normally portrayed as a horizontal timeline, similar to the image featured on the right. Defined as the infamous ‘March of Progress’, it shows the slow progression of man getting taller, the forehead becoming increasingly vertical, and the gradual transformation of posture. It depicts the natural appearance, or so what we have presumed was the natural appearance of our ancestors.

 However, I think that a good way in which to portray Human evolution is by the following diagram, as you can see, it is not completed in great detail however it shows that man hasn't just evolved as one organism, with the species evolving and changing as one, but the more realistic idea of natural selection. The process in which a species can coexist with its phenotype (polymorph) preceding the eventual fate that one will be gradually pushed to the breaches of extinction.

This brings me back to the initial point of interest – Atavism. With the ancestors of man developing in different ways, it means that they will begin to have different features; one phenotype may have lost a feature, for example, a tail whilst gaining new features such as opposable thumbs. Obviously this would have happened over the time period of millions of years; however it does show a possible theory of how we have grown apart from the ape like being we once resembled. Below is featured an example of a polymorph.

With a recombination of genes occurring within an organism, it is using a similar genetic formation as one that has pre – existed in our ancestors. So when an Atavism does occur, it would be interesting to see how the genes changed. By looking at how the genetical structure of our ancestors, through modern day Atavisms, we may be able to understand how we have changed and possibly why this has happened. If we were able to claim that information, a question I would be asking is, if we look at the changes of the past can we predict our future? Will we be able to genetically modify man in order to develop at a quicker rate? What will the ethical voice of reason say in response to this idea of genetically modifying?

When thinking about the future of man, it leads me into thought processes of whether or not Atavism should be thought of negatively; perhaps it is just the next step of human evolution. Will we develop to attain features of animals? I know the next statement is possibly slightly shallow; however it does raise an interesting thought. In ‘The Amazing Spider Man’ (2012), the idea of genetic coding is effectively what the film is about. It’s suggesting the idea of taking combinations of genes from animals that have certain features in order to enhance the human body. For example the film focuses on the ability to regenerate limbs. Now, I’m not saying that we should base all our scientific theories on the Spiderman Films however I do think that it is an interesting thought.

If we were to be able to incorporate features like regeneration of the body into humans, we could become extremely powerful beings. This isn't necessarily a good thing. We have already manipulated the world, to accustom our needs however this would be the next step. Although, genetic coding could be used for very sinister reasons, it could also provide incredible medical enhancements throughout the world. If we were able to grasp the control of abilities to regenerate or of immunity, it may help us find a solution in terms of curing diseases such as leprosy.

Relating back to Atavism, the idea that we start to take on the appearance of our ancestors isn't the only aspect of it.  It also includes throwbacks in our behaviourisms. For example, individuals who demonstrate violent, dominant and primitive behaviour are likely to have a mental throwback. In which characteristics reform and produce members of society that according to Cesare Lombroso are more likely to be capable of participating in criminal activity. He linked this to their appearance, saying that men who had wider faces, a more sloped forehead and larger ears, were more likely to be convicted for criminal behaviour. This is not to say that all mean with appearances that follow this pattern are hard-core criminals. It was merely a generalisation from data.

Forming a conclusion, I have learnt many a thing throughout this little exploration into the world of Atavism. Although this is only my opinion I think that Atavism is a wondrous thing. It could really help us in the future and has given me an insight into the world of genetics. It may be difficult for the people who possess these Atavisms however, I do think of them as extremely interesting. I shall leave you with a quote that I thought was rather thought provoking.

"What is happening is not random - it’s not cells running amok. It’s cells following an ancient program." - Paul Davies

For more information on this fascinating topic please look at:

http://en.wikipedia.org/wiki/Atavism

http://evolution.berkeley.edu/evosite/evo101/IIIA1Genotypevsphenotype.shtml

http://science.howstuffworks.com/life/evolution/atavism.htm

Lauren Frame  -  29^th October 2013

Cholesterol: The Good, The Bad and The Ugly.

Cholesterol: The Good, The Bad and The Ugly

Cholesterol is a compound found in most body tissues. It is an essential substance due to its role in the cell membrane, bile acids and the production of vitamin D and hormones. Cholesterol can't dissolve in your blood which means it is transported in your bloodstream by carrier proteins, called lipoproteins. There are two types of lipoproteins that carry cholesterol: High-density lipoproteins (HDL) and Low-density lipoproteins (LDL). 

Cholesterol is vital. It is essential to every cell in the body and thus involved in the reproductive system, brain activity, movement of muscles, structure of bones and subsequently without cholesterol we would cease to exist. This is why our bodies make it, the chemical formula is C27H46O. There is no good or bad version of this formula. Due to cholesterols non-polar hydrocarbon tail, it is not water soluble- which is why it can not be transported by the blood but is carried by lipoproteins. 

You are all no doubt aware of the popular hypothesis on the relationship between cholesterol and heart disease. Lipoproteins which carry cholesterol- like mentioned earlier- are categorised: LDLs carry cholesterol from the liver to other cells, where it is needed; HDLs carry 'recycled' or excess cholesterol back to the liver to be transported out the body. Both have important purposes, yet they have been separated into "Good" and "Bad" . In the words of good and bad, LDL is the bad one as it collects in the walls of blood vessels, causing the blockages of arteriosclerosis. However, none of this is true. In the Framingham Heart Study, it was shown that intake of cholesterol has no correlation with heart disease. In figure 1 you can see that men and women with above average cholesterol levels had nearly identical rates of heart disease as people with average cholesterol levels. 

Fig. 1

The man responsible for the "diet-heart hypothesis", Ancel Keys, based the ideas on early experiments with chickens and rabbits. However, due to chickens and rabbits being vegetarian, their physiology is not adapted to handling large amounts of cholesterol. But, we can not apply this information to humans (omnivores with significant differences in physiology). After a life time of research he realised this:

“Cholesterol in food has no impact on cholesterol in the blood and we’ve known that all along.” Ancel Keys.

Though it is still accepted as gospel truth by the general public and many medical professionals, most researchers and the scientific community now believe the primary causes of heart disease are inflammation and stress. If cholesterol did cause heart disease, all genders, races and ages would be affected as it is a natural substance in all people. However, this is not true. A recent study at the  Conference on Low Blood Cholesterol, showed women are 300% less likely to suffer from heart disease than men, despite having higher average cholesterol levels. Heart disease and most other terminal illnesses are brought about by ageing, life style choices and extreme dietary factors.

Cholesterol is commonly associated with high sugar diets. However, the logic behind this has been reversed. The disadvantages with a diet full of carbohydrates is not the fact it increases cholesterol but the fact sugar is later stored as fat, which can have long term complications. Do not think of cholesterol as something you should avoid from your food, as your liver produces it constantly. If you consume extra cholesterol, from food like eggs and meat, your body will only absorb it if it is needed. The cells lining the small intestine contain transporter molecules that absorb cholesterol. However, if your body does not require any more, there is another molecule that pumps the cholesterol back into the intestine to be eliminated. 

The reason sugar is linked with cholesterol is due to LDL being oxidised and carbohydrates causing oxidation. When LDLs are oxidised they can become small and dense which can be linked with heart disease. Additionally, when our diets include too much carbohydrates, blood insulin levels spike. As a result the bodies cells are told to produce more cholesterol. The build up in blood vessels, which cause heart disease, are not due to the intake of excess cholesterol but the affect sugar has on cholesterol and other substances in our body. So high cholesterol levels are usually achieved due to high 'carb' diets, not from foods that are high in fat and cholesterol. Therefore, by avoiding excess carbohydrates, we can avoid cardiac complications. 

Statins are drugs used to inhibit the production of cholesterol, in attempt to treat heart disease. They work due to having an anti-inflammatory affect, the fact they stop the body from producing a vital substance is an unfortunate side affect. If we reduce cholesterol, we are slowing all the vital processes in the body. One in 500 people have cholesterol levels which are too high, and this drug could be helpful for them. But, the majority of people are inhibiting the production of a substance involved in all life processes. 

Cardiology researchers are now turning away from the notion that saturated fat and cholesterol cause heart disease. After all, how could substances that we have been eating for thousands of years cause heart disease, which is a relatively new phenomenon? Cardiologists are finding instead that refined carbohydrates, which we have only been eating in significant quantities for about 100 years, are the most important dietary factor at the root of heart disease.  


So there you have it. Contrary to popular belief, cholesterol is not a dangerous poison that causes heart disease. Rather, it is an essential nutrient present in the cell membranes of all tissues of all mammals, and has some very important functions in the body. In fact, in many studies, low cholesterol has been associated with a reduced life span. 

The body makes cholesterol, there are a lot of things we need to worry about, but our body trying to kill us is not one of them!