DNA provides genetic information for development and functioning in the body, and reproductive purposes like passing the biological traits of parents to their offspring. Think of this term as the “genetic blueprint” of all life. DNA consists of three main parts. These include sugar groups, phosphate groups, and one of the five types of nitrogen groups (also known as nucleotides.)
A double helix is the name of the shape a DNA strand makes. For a visual representation, it resembles a twisted ladder. On the strands of this formation, the DNA alternates between sugar and phosphate groups. Sugar is essential in the double helix configuration since it allows cell replication. This means that the sugar in each cell helps pass down the genetic information of the parents to their offspring. Phosphate groups, on the other hand, are responsible for maintaining the structure of the helix. Along with that, phosphate groups are also in charge of activating molecules and proteins.
The five types of nitrogen groups are adenine (a), thymine (t), guanine (g), cytosine (c), and uracil (u). These sequences determine the genetic code that is given to the DNA strands. For instance, ATCGT could be for blue eyes, yet ATCGCT could be for brown eyes.
How these works are by the enzymes. They copy the information from DNA and transfer it to intermediary cells, much like ribonucleic acid or mRNA. The intermediary cells are then translated into a code. This code signifies the specific genetic information within the human body.
Finding and collecting DNA
DNA exists in most of the three trillion cells stored in your body. However, some things like red blood cells that have aged (or “matured”) don’t. Additionally, this list also includes mature skin, hair, and nail cells. DNA is located in the nucleus. A small portion of it can also be found in the mitochondrion of eukaryotes. Eukaryotes are any cell or organism that possesses a clearly defined nucleus. On the other hand, things like plants, animals, fungi, and microscopic creatures all have their genetic information in something called cytoplasm.
DNA can be collected through saliva, fingernail scrapings, blood, hair, skin, and teeth. For each of these listed items, the way it is collected varies. For example, the “buccal test.” This process would mean that saliva would be swabbed with a cotton stick. On the other hand, blood is collected by pricking your finger. DNA is found everywhere, not just in the body. It can be found in inanimate objects. Each of the following includes examples of these objects:
-
- Masks.
- Hats.
- Gloves.
- Clothes.
- Weapons.
- Used utensils.
- Used cigarettes.
- Bedding.
- Toothpicks.
- Eyeglasses.
- Hygiene tools (like washcloths, brushes, toothbrushes, and combs).
The History of DNA
Swiss chemist Johann Friedrich Miescher discovered DNA. Miescher had the goal of finding the components of “white blood cells.” These are the blood cells that contribute to the body’s immune system.
“Pus covered bandages” were his primary source for his experiments. To carry out these experiments, he mixed these bandages with salt-based solutions to break away the white blood cells. He added alkali right after. This is a chemical that dissolves in water, combines with acids to form salts, and makes acids less acidic.
The substance dissolved and formed a new shape. After this, he labeled this form as the “nuclein” since he believed it had something to do with the nucleus. It was only in 1874 when Miescher filially released his finding to the world in his book.
Albrecht Kossel was a biochemist who built off of the work from Miescher. By taking a further understanding of the nuclein, he determined that it was a nucleic acid and even separated it into five nucleotide bases that build our DNA. These included: adenine (a), thymine (t), guanine (g), cytosine (c), and uracil (u). Kossel renamed this “nuclein” as Deoxyribonucleic Acid. Over time, the purposes of DNA have varied. Thanks to their work, today we now know that this is our genetic blueprint.
By Khalyse Hemingway
Sources:
Genome.gov: Deoxyribonucleic acid
Nature.com: Replication
Forensicsciencesimplified.org: Sources of DNA evidence
Ancestry.com: Where is DNA found
Yourgenome.org: The discovery of DNA
Inset Image by Mayberry Health and Home Courtesy of Kevin Simmons Flicker Page -Creative Commons License
Featured Image Courtesy of The Kingsway School Flicker Page -Creative Commons License
