Introduction
DNA or deoxyribonucleic acid is the genetic material that carries and transmits the genetic instructions from parents to offspring. The information stored in DNA can be used to trace ancestry back through generations or even identify people by their unique set of genes. It was first identified by Johannes Friedrich Miescher in the late 1860s. The structure of DNA was later discovered by James Watson and Francis Crick in 1953.
Significance of DNA in Evolution
Deoxyribonucleic acid or DNA is the blueprint for all the inherited characteristics that are present in living things. It is a long sequence that is written in code which needs to be transcribed and translated so that a cell can make the proteins that are essential for the life processes. Any kind of changes in the DNA sequence could lead to changes in the proteins, and, in turn, they might translate into the changes in the traits that those proteins can control. Changes at the molecular levels tend to lead to the micro-evolution of species. In this article, we will take a look at what DNA is, the significance of DNA and the significance of DNA in evolution. Let us first learn about what DNA is and how it works in the several life processes of the human body.
The Universal Genetic Code
The DNA which is present in living things is highly conserved. DNA consists of four different nitrogenous bases, which code for all differences in the living things present on the Earth. Adenine, cytosine, guanine, and thymine are the four nitrogen bases that line up in a specific order. A group of three, or one codon, codes for one of the total 20 amino acids that are found on Earth. The order of these amino acids determines what type of protein is made.
Remarkably enough, only four of the nitrogenous bases, which make just 20 amino acids account for all of the diversity of life on Earth. No other code or system has been present or found in any of the living or once-living organisms on Earth. Organisms ranging from bacteria to humans to dinosaurs all have the same type of DNA system as a genetic code. This can point to evidence that all types of life evolved from just one single common ancestor.
Changes in DNA
All of the cells are pretty well-equipped with the way for checking a DNA sequence for any kind of mistakes before and after the process of cell division or mitosis. Most of the mutations, or changes in the DNA, are caught before the copies are made and these cells are destroyed. However, there are some times when even the small changes do not make much of a difference and would pass through the checkpoints. These mutations can add up over a period of time and change some kind of the functions of that particular organism.
If these mutations occur in the somatic cells, in simpler words, the normal adult body cells, these changes will not affect the future offspring. If the mutations occur in the gametes or sex cells, the mutations would get passed down to the offspring generation and might affect the different functions of the offspring. The gamete mutations would lead to microevolution.
Genes and Determination of Traits
Our genes tend to determine our bodies. They provide us with the biological information which makes us who we are today. Although the future developments in science and medicine might allow us to change parts of ourselves, presently, we cannot make any changes to our genetic code. For example, you cannot change the genes which provide you with your natural hair color. Instead, if you want to change your hair color, you would have to color or dye it. The same thing is true for so many disorders and diseases that have a genetic origin. You cannot change those genes once you inherit them from your parents.
Genes can also determine a few parts of your personality. Researchers have demonstrated that genes can relate to our sexuality, the development of certain addictions, how our moods tend to change, and several other elements of human psychology. However, if you know about any identical twins, you would already be able to realize how difficult these studies are. Even when they have the same genetic code, identical twins often tend to form varying personalities. However, a lot still remains to be learned in this field.
Even though the earlier theories that were related to genetic determination said that all human features were coded by genes, modern scientists understand the fact that the environment also tends to play a role in forming several of our physical traits, personality traits and characteristics, and illnesses. Additionally, the epigenetic effects might cause the genes to turn on and off, downregulate, or upregulate. Changing the way how a gene is expressed would change the trait that is produced, even if the basic DNA sequence of the gene does not change.
FAQs on Significance of DNA
1. What is the fundamental significance of DNA in all living organisms?
The fundamental significance of deoxyribonucleic acid (DNA) lies in its role as the primary genetic material. It acts as a comprehensive blueprint that carries all the hereditary instructions required for an organism's development, functioning, growth, and reproduction. Every cell in an organism contains a complete copy of this blueprint, ensuring the continuity of life and the transfer of traits from one generation to the next.
2. How does the double helix structure of DNA contribute to its significance?
The double helix structure is crucial to DNA's significance for two main reasons:
- Stability: The two-strand structure, with hydrogen bonds between the base pairs (A-T and G-C), provides chemical stability, protecting the genetic code from damage.
- Replication: The complementary nature of the strands allows each one to serve as a template during DNA replication. This ensures that genetic information is copied with high fidelity before cell division, which is essential for growth and heredity.
3. What is the significance of DNA replication for a species?
The significance of DNA replication is to ensure the precise and accurate transmission of genetic information. When a cell divides, each new daughter cell receives an identical copy of the DNA. This process is vital for:
- Growth and Repair: Allowing multicellular organisms to grow and replace old or damaged cells.
- Heredity: Passing on genetic traits from parents to offspring during reproduction, maintaining the continuity of the species.
4. Why is the universality of the genetic code considered a significant piece of evidence for evolution?
The genetic code—the set of rules by which DNA sequences are translated into proteins—is nearly universal across all known life forms, from bacteria to humans. This remarkable consistency is significant because it strongly suggests a common ancestry. It implies that all life on Earth evolved from a single ancestor that used this same code, which has been conserved through billions of years of evolution.
5. What is the significance of DNA mutations in the context of evolution?
While DNA is remarkably stable, occasional errors or mutations can occur. The significance of these mutations is that they are the ultimate source of all genetic variation within a population. While many mutations are neutral or harmful, some can result in new traits that provide a survival advantage. Natural selection can then act on this variation, leading to the gradual evolution of species over time.
6. What is the clinical significance of DNA analysis in medicine?
In medicine, the clinical significance of DNA analysis is immense. It allows for the diagnosis of genetic disorders by identifying specific mutations in a person's genes. Furthermore, it is central to the field of pharmacogenomics, which helps predict how an individual will respond to certain drugs based on their genetic makeup, leading to more personalised and effective treatments. It is also used in prenatal screening and identifying predispositions to complex diseases like cancer.
7. What is the significance of DNA fingerprinting in forensics?
DNA fingerprinting is significant in forensics because each individual (except identical twins) has a unique DNA sequence. By comparing DNA samples collected from a crime scene (like blood or hair) with the DNA of suspects, investigators can establish a highly accurate link between a suspect and the crime. Its significance also extends to identifying victims, resolving paternity disputes, and studying wildlife populations.
8. Beyond storing genetic information, what other roles make DNA significant in cellular processes?
Besides being a static storage molecule, DNA plays an active and significant role in cellular processes. Its non-coding regions, once considered 'junk DNA', are now known to be crucial for the regulation of gene expression. These regions contain sequences that act as switches, determining when, where, and to what extent specific genes are turned on or off. This regulatory function is essential for cell differentiation and responding to environmental changes.
