Unraveling the Secret Life of DNA

Audience: Middle and High School Students

Did you know if you stretched out all of your DNA, it would be approximately 10 billion miles long, which is enough to travel to and from the Sun more than 60 times? Photo by Braňo from Unsplash.

DNA molecules are the building blocks of life, and their hidden story has slowly been decoded by scientists for the last 160 years. DNA is the complex blueprint that holds the secrets of all living things, navigating the story of an organism's life in each twist and turn of its double helix. Also known as Deoxyribonucleic Acid, DNA contains the genetic information required for all living things to develop, survive, and reproduce. 

DNA exhibits a unique double-helix structure, which includes two intertwined strands of nucleotides, with each nucleotide containing a sugar, phosphate group, and nitrogenous base. To begin, Deoxyribose is the sugar molecule found in DNA which acts as the backbone for DNA strands. Deoxyribose connects the nitrogenous bases and phosphate groups together. These phosphate groups form the "rails" of the DNA helix. They are made up of a phosphorus atom surrounded by oxygen atoms. Lastly, the "steps" of the ladder are the nitrogenous bases that consist of adenine, thymine, cytosine, and guanine. The genetic instructions in DNA are carried by these nitrogenous bases, which form pairs of adenine and thymine, as well as cytosine and guanine. DNA's double helix structure is important because it allows for the compact and secure storage of large amounts of genetic information. Its structure ensures the successful replication of DNA, since the two strands can split and serve as templates to create identical copies of DNA.

As mentioned previously, DNA contains the instructions that control an organism's growth and development. Beginning with a single fertilized cell, DNA directs the cell through the complicated process of cell division and specialization. As the organism develops, DNA manages the formation of tissues and organs, guaranteeing each cell completes its role in producing a fully functioning organism. Additionally, DNA plays a vital role in determining the traits that are passed down from generation to generation, such as eye color, hair color, and blood type. Specifically, these traits are determined by alleles, which are different versions of a gene that can inhabit the same place on a chromosome. These alleles are inherited by an offspring from both of their parents, and they determine the offspring's expressed traits. Certain alleles are dominant, causing them to outweigh the effect of other alleles when determining an organism's traits. On the other hand, recessive alleles only affect the result of a trait when combined with another recessive allele. For example, a dominant gene responsible for brown eyes can mask the effect of a recessive allele for blue eyes, meanwhile, the trait of blue eye will only appear if both alleles are recessive. 

In addition to alleles determining every trait, DNA can undergo mutations that result in the formation of new traits, allowing organisms to better adapt to their environment. Mutations are changes or flaws in the genetic code that can develop at random or due to other environmental factors. Mutations can have varying effects: causing no visible implications, being  harmful, or introducing new traits that provide an advantage for survival. For example, a mutation could result in an organism having Albinism which results in a lack of melanin. This can negatively affect animals because it makes their fur white, causing them to become highly vulnerable to predators due to their lack of camouflage. On the other hand mutations can also be beneficial, such as a mutation that increases disease resistance. These types of mutation can improve an individual's ability to survive and thrive in their environment. Overall, mutations can help produce a wide range of characteristics in a population. This increases genetic diversity amongst species, improving their ability to survive in their particular environment. 

Over time through years of research scientists have been able to develop a way to test DNA for various things, one of those being mutations. Genetic testing is typically done by first collecting a sample, like blood or saliva. The DNA is then examined in a lab to find specific genetic markers or mutations, which are linked to different diseases or traits. Genetic testing is extremely important because it can identify hereditary diseases and predict if one is prone to contracting certain illnesses. Such genetic testing has been used to help millions of people start preventative treatments early on to reduce their risk of contracting various illnesses. Another way genetic testing is often used nowadays is to track ancestry. Many people seek to understand their origins and ancestral lineage. One great way to determine this is by taking an ancestry test. Ancestry tests use DNA to track your family's roots, pinpointing where your ancestors lived and what regions they came from. These tests can uncover unsuspected connections people have with various parts of the world and, in some cases, they can offer opportunities to contact distant relatives. These tests are very interesting because they teach people more about their family history and cultural heritage, giving numerous individuals a stronger connection to their roots.

Nonetheless, the innovations and discoveries regarding DNA do not end there. Recently, in September of 2024 researchers at Princeton University found a new way to study the genome. According to Princeton Engineering scientists were able to bend DNA strands with light, providing them a new perspective into genomes. One of the principal investigators of the study,  Cliff Brangwynne stated that they have, “turned droplets into little fingers that pluck on the genomic strings within living cells.” Essentially, the scientists have found a way to use light to grow two droplets of liquid inside a cell's nucleus. Then they combine them, and shrink the combined droplet to pull the genes together as it gets smaller. This method allows scientists to move gene strands in a controlled way, which gives them the opportunity to study different diseases within DNA like in cancer. This study is revolutionary because it provides us with a better understanding of how diseases like cancer behave at the genetic level. Understanding how genes behave and interact in disorganized states could help scientists develop more effective treatments against them. Ongoing DNA research, such as the one discussed above, assists in the identification of genetic mutations associated with diseases such as cancer. This understanding allows for better prevention of such diseases, and the creation of more effective treatments for them. 

Bibliography

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“Princeton Engineering - Researchers Bend DNA Strands with Light, Revealing a New Way to Study the Genome.” Princeton Engineering, 19 Oct. 2024, engineering.princeton.edu/news/2024/09/09/researchers-bend-dna-strands-light-revealing-new-way-study-genome. Accessed 7 Feb. 2025.