Mutations - What, How, Who cares
Mutations. They lead to X-men, creepy creatures in the sewers, and even cancer. "Mutation" is a word that is used often in both the scientific community and in mainstream media which is why we wanted to provide you with some background on what exactly the word "mutation" means and what role it has in human biology.
Definition: According to the National Library of Medicine a mutation is
"a permanent alteration in the DNA sequence that makes up a gene, such that the sequence differs from what is found in most people."
In other words, its when your DNA sequence has a typo. Lets back up though and understand what the DNA is and what its primary function is.
Most people understand that DNA is the building block that holds all the information to make you...you. You might think of DNA as being an autobiography, your own little book. Books tell a story by combining letters to make words, words to make sentences which become paragraphs and vuala - book. Your DNA is very similar. It uses DeoxyriboNucleic Acids (DNA) rather than letters. By combining these into long strings of patterns they begin to make sentences which are read by proteins in your cell. The sentences provide instructions on how to make more proteins and other components the cell needs in order to be functional. Every cell in your body has this book of DNA, some cells just read it differently which causes them to become a skin cell, or a liver cell, or a brain cell (nerds). Proteins produced from your DNA contribute to every function in the cell including policing cellular activities to make sure it doesn't go rogue.
Its not surprising that a mutation, or change in the sequence of letters, can cause some problems if it disrupts a regulatory command. Some proteins are made to stop a cell from replicating. If you lose that protein because of a mutation, wild card problems can happen.
What kind of mutations are there?
Many! The National Health Library lists some seven different categories for mutation which differ mostly in their effect. In the simplest terms, you can either gain letters,deoxyribonucleic acids, where you're not supposed to have them (an insertion mutation), you can lose letters where you had them (deletion mutation), or you can accidentally put the wrong letter in place (this one can go in multiple categories). The end result could be an effed up sentence. For example:
Go pick the kids up.
If there is a mutation in this DNA sequence that replaces the letter "p" with "k", it then reads:
Go kick the kids up.
A little different meaning which could have dire consequences. Another mutation that would change this sentence would be to delete the letters "ki". Now it reads:
Go pick the ds up.
You can start to see how easy it is to make a normal command go wrong with a simple mistake.
How do mutations happen though?
Your DNA gets read in its entirety and then copied down, letter for letter every time your cells replicate (split into two). This ensures both new cells have a complete copy of the DNA. This process is not perfect though, just as it wouldn't be perfect if you or I tried to hand copy an encyclopedia word for word. Typos happen. Most of the time, your cells catch these errors and correct them, and other times they don't. Most of the time, the mutation has no real effect. A mutation isn't a problem if it doesn't change the meaning of the sentence. Go back up to our example sentence and insert the letter "p" after the word "up". Yeah, its not the original sentence but the point gets across so no harm no foul.
Aside from normal mistakes made while replicating the DNA, other factors can cause the cell to mess up. For example, your body needs oxygen to make nucleotides. Without it the process of replication can be slowed down and the DNA may begin to fall apart if it goes to slow. A panicked attempt to keep the DNA together is initiated where the cell essentially starts taping together pieces of DNA that don't belong together just to keep the overall structure in tact.
This is likely to produce a mutation. Normal cells have a much more controlled response, but when proteins responsible for this controlled response are overwhelmed or lost (maybe due to a mutation), problems can happen. One good example is the BRCA gene. This protein is involved in repairing damaged DNA. Mutations often happen at this site in the DNA which cause the protein to be lost and is a major factor in causing breast cancer.
Cancer cells experience many mutations often as a result of rapid replication leading to this panicked attempt to protect the DNA. There are many reasons cancer cells experience mutations, we'll have a post coming on that soon! But for now, we'll simply say they have problems protecting their DNA and find themselves in less than ideal situations for making perfect DNA copies. High mutation rate means they are able to evolve within your body and can potentially evade chemotherapy by rapid evolution.
Can mutations be a good thing?
Absolutely! As we alluded to earlier, mutations lead to the process of evolution. When your DNA sequence changes just slightly, it might turn your hair color red instead of black. This change doesn't cause cancer, but it might cause you to survive if you live in an environment where predators see everything that isn't red. Every generation has many many mutations which get passed on when the sperm or egg contains a mutation. Over thousands of years this has lead to...us, and will lead to future human's that may look pretty different from you or I.