What Are rDNA and cDNA? Definitions, Differences, and Importance
Modern science has already been transformed by DNA technology. Numerous hints about the secrets of human behaviour, illness, evolution, and ageing can be found in DNA. Cloning, PCR, recombinant DNA technology, DNA fingerprinting, gene therapy, DNA microarray technology, and DNA profiling are a few examples of contemporary developments in DNA technology. The fields of health, forensic science, environmental research, and national security have already started to be influenced by these technologies. Two types of DNA that can be created using modern DNA technologies are rDNA and cDNA.
What is rDNA?
Recombinant DNA technology is the name given to the process of creating artificial DNA by fusing DNA from various sources with various genetic components. Genetic engineering is the term used to refer to recombinant DNA technologies.
In 1968, Swiss microbiologist Werner Arber made the discovery of restriction enzymes, which led to the development of recombinant DNA technology. It's harder than it sounds to splice the desired gene into the host's genome. It entails choosing the ideal vector with which to integrate the intended gene and create recombinant DNA after choosing the appropriate gene to be administered to the host.
What is rDNA?
Reverse transcription, the process of creating DNA from an RNA template, results in complementary DNA (cDNA). Reverse transcriptases (RTs) direct the synthesis of the first strand of cDNA, which can be used directly as a template for the Polymerase Chain Reaction, using an RNA template and a short primer complementary to the 3' end of the RNA (PCR). Reverse transcription and polymerase chain reaction (RT-PCR) allows for the detection of low-abundance RNAs in a sample and the creation of the corresponding cDNA, making it easier to clone low-copy genes. As an alternative, DNA Polymerase I and DNA Ligase can be used to double-strand the first-strand cDNA.
What Similarities Do rDNA and cDNA Share?
These kinds of DNA can be created using current DNA technology.
Both DNA types are created by unique enzymes.
They are created in particular labs.
There are several uses for both forms of DNA in biotechnology, medicine, and agriculture.
Differences Between rDNA and cDNA
Interesting Facts
Human dna is 99.9% similar
The size of DNA in humans is 2.2 metres larger than the cell size.
DNA fingerprinting is the technique used to identify criminals, and also used for paternity testing
Viruses are not living, they do not get any place in whittaker's classification
Important Questions
1. What is cDNA technology?
Ans: cDNA microarray is one of the important methods for studying gene expression in many organisms. It is also used for mapping of genomic DNA and polymorphism.
2. What is rDNA used for?
Ans: rDNA is used to manipulate DNA fragments to study them in the lab. It uses many laboratory methods to put a piece of DNA or gene of interest in a vector cell.
3. What is the process of making cDNA?
Ans: The process of formation of DNA from RNA through the reverse transcription leads to formation of cDNA. cDNA is used as a template in many downstream applications.
Practice Questions
What does cDNA mean?
Why is cDNA used in recombinant technology?
How is mRNA converted to cDNA?
What is the difference between cDNA and DNA?
Key Features
In this article, we have studied about cDNA and rDNA, differences and similarities between cDNA and rDNA.
Modern DNA technologies have been discovered to be helpful in genetic engineering, illness prevention, boosting agricultural productivity, diagnosing ailments, and catching criminals.
Two forms of DNA that can be created using current DNA technologies are rDNA and cDNA. By combining the DNA of two various creatures, rDNA is created. On the other side, reverse transcription is used to create cDNA from mRNA. So, this sums up how rDNA and cDNA vary from one another.
FAQs on rDNA and cDNA: Concepts, Examples, and Applications
1. What is recombinant DNA, or rDNA?
Recombinant DNA (rDNA) is an artificial form of DNA that is created by combining DNA fragments from two or more different sources. Scientists use special enzymes to 'cut' a specific gene from one organism and 'paste' it into the DNA of another, like a bacterium. This creates a new, hybrid DNA molecule that does not exist in nature.
2. What is complementary DNA, or cDNA?
Complementary DNA (cDNA) is a DNA copy that is made from a messenger RNA (mRNA) template. It is created using an enzyme called reverse transcriptase. Since mRNA only contains the coding sequences (exons) of a gene, cDNA represents only the parts of a gene that are actively being used to make proteins.
3. How is rDNA technology used in real life?
A classic example of rDNA technology is the production of human insulin for diabetics. Scientists insert the human insulin gene into the DNA of bacteria using rDNA technology. These genetically modified bacteria then multiply rapidly, producing large quantities of pure human insulin, which is much safer and more effective than insulin sourced from animals.
4. What are the basic steps to create recombinant DNA?
The process generally involves four main steps:
- Isolation: The desired gene and the vector DNA (like a plasmid from bacteria) are isolated.
- Cutting: Both the gene and the vector are cut with the same restriction enzyme to create compatible 'sticky ends'.
- Ligation: The desired gene is inserted into the vector, and an enzyme called DNA ligase joins them together to form the rDNA.
- Transformation: The recombinant DNA is introduced into a host organism (e.g., bacteria), which then replicates it.
5. What is the main difference between genomic DNA and complementary DNA (cDNA)?
The key difference is what they contain. Genomic DNA represents an organism's entire genetic blueprint, including both coding regions (exons) and non-coding regions (introns). In contrast, cDNA is made from mRNA and only contains the exons. Therefore, cDNA is a snapshot of the genes that are actively being expressed to make proteins at a specific time.
6. Why is reverse transcriptase a crucial enzyme for creating cDNA?
Reverse transcriptase is essential because it performs a unique function: it synthesizes DNA using an RNA template. This process is the 'reverse' of normal transcription where DNA is used to make RNA. Without reverse transcriptase, we could not create a stable DNA copy (cDNA) from a fragile mRNA molecule, making it impossible to study or clone the expressed genes of an organism.
7. How are rDNA technology and PCR different from each other?
Although both are key biotechnologies, they have different goals. rDNA technology is about combining DNA from different sources to create a new genetic combination, like inserting a human gene into a plasmid. Its purpose is to create a modified organism or produce a specific protein. On the other hand, Polymerase Chain Reaction (PCR) is a technique used to make millions of copies of a specific segment of DNA. Its goal is not to create new DNA but to amplify an existing DNA sequence for analysis.
8. Why can't scientists just insert a human gene directly into bacteria to produce a protein?
Human genes contain non-coding sections called introns, which are naturally removed from the mRNA before a protein is made. Bacteria do not have the necessary mechanism to remove these introns. If a human gene were inserted directly, the bacteria would read the introns as part of the code, resulting in a faulty, non-functional protein. By creating cDNA first, we use a version of the gene that already has the introns removed, allowing the bacteria to produce the correct protein.
