We hear about them all the time, but what is a gene?

Nathan ScrimeourWe hear about them all the time – this gene causes a disease, or that gene is important for normal heart function. Most people could tell you that your genes are made of something called DNA, that you inherit them from your parents and pass them on to your children, and that they determine much of who you are and what you look like. But how do we get from genes to an entire organism, and what control do we have over our genes?

To answer these questions, we need a basic understanding of what is known as the “central dogma” of biology, which describes the one way flow of genetic information. While the reality is more complex than this, the flow can be simplified as such:

Read also: Tailored exercise for your DNA

DNA (genes) – a permanent store of genetic information

(transcription)

RNA (messenger) – short, temporary copies of a single gene transcribed from DNA

(translation)

Protein – functional molecules that are built by translating genetic information from RNA

DNA blå

Each of the three stages is chemically different, but they all share two critical properties.

  1. They are made up of repeating units that are bound together like links in a chain. In the case of DNA and RNA, each link in the chain can be one of four different bases; in the case of proteins, links can be any of 20 different amino acids.
  2. The sequences of these different links are critical. The base sequence of DNA determines the base sequence of RNA, which in turn determines the amino acid sequence of proteins; the amino acid sequence of a proteins determines that protein’s shape and function.

Read also: Genetics and cardiovascular disease

We can think of these different links in DNA or protein as like letters in an alphabet. The English alphabet has 26 letters, and taken alone, each of them is quite meaningless. However, we can put them together one after another in many different sequences to form meaningful words, sentences and entire novels with almost limitless possibilities. In the same way, proteins, built from just 20 different amino acids, perform the vast majority of all functions in any organism, whether it be breaking down sugars and fats into energy, moving our muscles, sensing the world around us, or providing structure to cells and tissues.

Read also: Why do some people get fitter than others?

The genes we are born with are, for the most part, the genes that we die with. Their sequences are rarely changed, and in that regard, our genes cannot be controlled. What can be changed, however, are the processes that come afterwards. Our behaviour (such as diet and exercise) and our environment can turn transcription and translation on or off, or make small modifications to proteins in order to turn their function on or off.

Nathan Scrimgeour, senior engineer at CERG

This entry was posted in Genetics, In English and tagged , , , , by CERG. Bookmark the permalink.

About CERG

The Cardiac Exercise Research Group (CERG) at the Norwegian University of Science and Technology (NTNU) seeks to identify the key mechanisms underlying the beneficial effects of physical on cardiac health in the context of disease prevention and treatment. Named the K.G. Jebsen Center for Exercise in Medicine under Professor Ulrik Wisløff's leadership in 2011, CERG uses both top-down and bottom-up approaches to combat lifestyle-related disease.

3 thoughts on “We hear about them all the time, but what is a gene?

  1. Nice and very simplified post on genes, Nathan Scrimgeour! Thanks. What is your take on gene editing? I’ve recently seen many discussions from potential benefits to ethical dilemmas. Looking forward!

    • Hi Amit, thanks very much!

      I actually wanted to write about something like epigenetics or gene editing! However, I thought that a post such as this one would serve as a nice base for readers completely unfamiliar with genetics so that I (and other CERG researchers) can start to post about more complicated concepts here in the future… so I hope we will have some more blog posts on these topics coming up!

      But to briefly answer your question: The CRISPR/Cas9 method of genome editing has been in the news a bit in 2015, and has already proven to be an extremely versatile, affordable, and technically simple tool in the generation of animal models for experimentation. The leap to using such a technique on human embryos is an exciting prospect but has some limitations and poses a lot of obvious ethical dilemmas.

      The technique may be useful for treating genetically simple conditions such as cystic fibrosis or Huntington’s Disease, and in my opinion, in these severe and well understood cases it is definitely worth further investigation. However even if this does prove to be possible, the majority of traits and medical conditions are much more complicated, implicating many genes and many environmental and lifestyle factors. The diseases with genetic components that are the most common causes of death in the developed world, such as cardiovascular disease, cancer and diabetes, will not be so easily prevented by genome editing.

      • Hi Nathan, thank you for getting back to me. Nice to read your comments on gene editing. Yeah, we might find it difficult to prevent multifactorial diseases (such as cardiovascular disease, cancer and diabetes) with genome editing. I am planning to set up a new cardiovascular diseases project (involving omics discipline) at the Computational Medicine Research Team in Oulu, Finland. It would great to see advances in the interpretation of genotyping results.

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