Evolution & Scoliosis

Evolution, as it pertains to biology, is a gradual modification of living things over time. This change happens through populations of organisms. Evolution is the most important concept in biology because all living things are by-products of evolution.

The process takes place through population genetics, when allele frequencies change. This can happen in numerous ways. These are known as the Four Forces of Evolution:

1. Mutations – When a new genetic variation is created in a gene pool.

2. Gene flow – When organisms move into or out of a population. Both the population they leave and the one they enter can change.

3. Genetic drift – A random change in allele frequencies that occurs in a small population.

4. Natural selection – When there are differences in fitnesses among members of a population. Some individuals will pass more genes to the next generation, which causes allele frequencies to change.

In this entry, I will be relating my project topic, Scoliosis, to the concept of evolution. I have three aspects to share as a result of my findings.

1. A Gene Associated Idiopathic Scoliosis Identified

During previous research, I came across a study by Japanese scientists that linked the cause of scoliosis with a genetic explanation. This experiment showed that a certain gene, GPR126 on chromosome 6, increases susceptibility to scoliosis when present. This is the first gene to ever be linked with scoliosis. More research is required in order to prove the connection. 

This study of genes associated with scoliosis closely ties in with evolution, since evolution is a study of genes.

For more information on scoliosis and genes, please visit my “Scientific Articles” post: https://scoliosisandbiology.wordpress.com/2013/12/08/scientific-articles/ (Article #3)

2. Evolution Of The Human Spine

Scoliosis is a disorder of the human spine. If we look more closely at the evolution of the spine itself, we can see why abnormalities and disorders are actually quite common. According to an article on Sciencemag.org, “evolution doesn’t ‘design’ anything…it works slowly on the genes and traits it has on hand, to jerry-rig animals’ and humans body plans to changing habitats and demands.” The article discusses several issues of the human body’s anatomic design that can cause problems for some people. One example of this is the structure of the spine. The human spine, which is essentially the anchor of the body, has an “S” shape. Due to this natural curvature, any weight imposed on the spine (weight of head, pressure from carrying things, or impact sports such as gymnastics or football) can lead to problems, such as general back pain or slipped discs. 

This article begs the question, could scoliosis be a by-product of poor evolutionary construction? Though the article doesn’t mention scoliosis, one theory on the cause or worsening of the abnormality is too much pressure placed on the spine (for example, young children carrying heavy backpacks), which causes a curvature.

3. Scoliosis In An Orangutan Experiment

I decided to look into further detail on the issue of scoliosis and evolution by researching if apes, who are in theory the ancestor of humans, ever develop the condition.

I came across an experiment done in the UK on scoliosis in an orangutan, a member of the great ape family. This orangutan was diagnosed with scoliosis, but in the conclusion of the study it was noted that the diagnosis was unlikely. From the background data, we can see that no case of scoliosis has ever been reported in an ape. Also the study found some factors that were atypical, including that the ape was male and the curve was short.

Although more research would be needed to confirm, we can see that scoliosis is not nearly as common in apes as it is in humans. This makes the connection to evolution that it was most likely something that occurred during the evolution of apes to human, providing more evidence to the second point made in this post.

For more information on scoliosis in animals, please visit my “Scientific Articles” post: https://scoliosisandbiology.wordpress.com/2013/12/08/scientific-articles/ (Articles # 1&4)
References
Gibbons, A. (2013). Human evolution: pain came with gain. Science Now. Retrieved
December 7, 2013, from http://news.sciencemag.org/evolution/2013/02/human-evolution-gain-came-pain
Krogh, D. (2011). Biology: A Guide to the Natural World.  San Francisco, CA:
Benjamin Cummings.
Imperial College School of Medicine. (2003). Scoliosis in an orangutan. PubMed.gov.
Retrieved December 5, 2013, from http://www.ncbi.nlm.nih.gov/pubmed/12671370
RIKEN (2013, May 12). Gene associated with adolescent idiopathic scoliosis
identified. ScienceDaily. Retrieved October 2, 2013, from http://www.sciencedaily.com/releases/2013/05/130512140943.htm
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