Difference Between rDNA and cDNA

The key difference between rDNA and cDNA is that rDNA is the recombinant DNA that is formed by joining the DNA of two different organisms, while cDNA is the complementary DNA that is formed from mRNA by reverse transcription.

DNA technology has already revolutionized modern science. DNA holds many clues of some of the mysteries behind human behaviour, disease, evolution, and aging. The recent advances in DNA technology include cloning, PCR, recombinant DNA technology, DNA fingerprinting, gene therapy, DNA microarray technology, and DNA profiling. These technologies have already begun to shape medicine, forensic sciences, environmental sciences, and national security. rDNA and cDNA are two types of DNA that can be synthesized through new DNA technologies.

CONTENTS

1. Overview and Key Difference
2. What is rDNA
3. What is cDNA
4. Similarities – rDNA and cDNA
5. rDNA vs cDNA in Tabular Form
6. Summary – rDNA vs cDNA

What is rDNA?

rDNA refers to the recombinant DNA formed by joining the DNA of two different organisms. Recombinant DNA is a piece of DNA that has been created by combining at least two DNA fragments from two different sources. As recombinant DNA is produced by the material from two different species, recombinant DNA molecules are also called chimeric DNA. Recombinant DNA technology uses bacterial derived enzymes called restriction endonucleases, which act like scissors to cut DNA. This leads to the production of sticky and blunt ends. Later, the DNA sequences originate from different organisms joining together to create chimeric DNA molecule. For example, plant DNA can be joined to bacterial DNA, or human DNA can be joined with fungal DNA.

Using rDNA technology and synthetic DNA, any DNA sequence can be created and introduced into any living organism. Recombinant proteins are the proteins produced from rDNA. These recombinant DNA encoding proteins are only produced in the host organism if the rDNA is introduced to the host organism through a specialized expression vector. Recombinant DNA differs from genetic recombination as it results from artificial methods in test tubes. Moreover, recombinant DNA is widely used in biotechnology, medicine and research, such as recombinant chymosin, recombinant human insulin, recombinant human growth hormone, recombinant clotting factor VIII, recombinant hepatitis B vaccine, etc. Recombinant DNA technology is also used for the diagnosis of HIV infection. In the plant sciences, recombinant DNA technology is applied in golden rice production and the production of insecticide-resistant and herbicide-resistant crops.

What is cDNA?

cDNA refers to the complementary DNA that is formed from mRNA by reverse transcription. In genetics, complementary DNA originates from a single-stranded RNA molecule such as mRNA or micro RNA. This reaction is called reverse transcription. The enzyme reverse transcriptase catalyzes this reaction. When scientists want to express specific proteins that are normally not expressed in a cell, they will transfer the cDNA that codes for the protein into the recipient cell.

In molecular biology studies, cDNA is also generated to analyze transcriptomic profiles in bulk tissue, single cells, or single nuclei in assays such as microarrays and RNA-seq. Moreover, cDNA is naturally produced by retroviruses. These viruses integrate cDNA into the host genome to create proviruses. Furthermore, complementary DNA is often used in gene cloning or as gene probes. cDNA is also used in the creation of a cDNA library.

What are the Similarities Between rDNA and cDNA?

• These types of DNA can be synthesized from modern DNA technologies.
• Both types of DNA are produced using specific enzymes.
• They are produced in specific laboratories.
• Both types of DNA have wide applications in biotechnology, medicine, and agriculture.

What is the Difference Between rDNA and cDNA?

rDNA is the recombinant DNA that is formed by joining the DNA of two different organisms. In contrast, cDNA is the complementary DNA that is formed from mRNA by reverse transcription. So, this is the key difference between rDNA and cDNA. Furthermore, rDNA is only produced through artificial methods, while cDNA can be produced through both natural and artificial methods.

The following infographic presents the differences between rDNA and cDNA in tabular form.

Summary – rDNA vs cDNA

Modern DNA technologies have found to be useful in pharmacology, genetic engineering, disease prevention, increasing agricultural production, diagnosis of diseases, and detection of crimes. rDNA and cDNA are two types of DNA that can be synthesized through modern DNA technologies. rDNA is formed by joining the DNA of two different organisms. On the other hand, cDNA is formed from mRNA by reverse transcription. Thus, this is the summary of the difference between rDNA and cDNA.

Reference:

1. McCooey, Matt Kinsey and Beth. “The Basics of Recombinant DNA.” An Introduction to Recombinant DNA.
2. “Complementary DNA.” ScienceDirect Topics.

Image Courtesy:

1. “Recombinant formation of plasmids” By Minestrone Soup at English Wikipedia (CC BY-SA 3.0) via Commons Wikimedia
2. “RT PCR Model” By Lokeshthimmana – Own work (CC BY-SA 4.0) via Commons Wikimedia