What is the Difference Between Replication and Duplication of DNA

The main difference between replication and duplication of DNA is that replication is the synthesis of an exact replica of DNA while duplication is the doubling of the amount of DNA as a result of replication. Furthermore, the replicated DNA strand is complementary to the template strand while gene duplication is the repeating of a part of a gene.

Replication and duplication are two mechanisms that increase the amount DNA inside the nucleus. They occur during the S phase of the cell cycle prior to nuclear division.

Key Areas Covered

1. What is Replication
     – Definition, Process, Importance
2. What is Duplication
     – Definition, Significance, Gene Duplication
3. What are the Similarities Between Replication and Duplication of DNA
     – Outline of Common Features
4. What is the Difference Between Replication and Duplication of DNA
     – Comparison of Key Differences

Key Terms

DNA Amount, DNA Polymerase, DNA Replication, Duplication, Gene Duplication, Sister Chromatids

What is Replication

Replication is the process that synthesizes an identical copy of the double-stranded DNA molecules in the cell. It occurs in both eukaryotic and prokaryotic cells. The main function of DNA replication is increasing the amount of DNA in the cell in twice as the cell undergoes division to produce daughter cells. This allows each daughter cell to contain the exact amount of DNA as the parent cell.

Figure 1: DNA Replication

Generally, DNA is a double-stranded molecule, consisting of two DNA strands. Each DNA strand serves as a template for the synthesis of new DNA. The main enzyme responsible for DNA replication is DNA polymerase. In addition, several enzymes including DNA helicase, RNA primase, etc. are involved in this process. DNA helicase unwind the double-stranded DNA to form the replication fork. Then, RNA primase adds a primer to the DNA templates to initiate DNA replication. Next, DNA polymerase adds complementary nucleotides to the template strand. The incoming nucleotides are covalently linked to the newly synthesized DNA strand via phosphodiester bonds. DNA replication occurs in a semi-conservative manner since one strand of each newly-synthesized double-stranded DNA is an old strand.

What is Duplication

Duplication is doubling of the amount of DNA as a result of DNA replication. During DNA replication, an exact replica of each chromosome is synthesized. This doubles the amount of DNA inside the cell. Thus, each chromatid gets doubled and is now called the sister chromatids. They are held together from the centromere. Hence, the number of chromosomes in the cell does not increase. Moreover, though the amount of DNA has increased by twice, the ploidy of the cell remains the same.

Figure 2: DNA Duplication

In addition to DNA duplication, there is another phenomenon called gene duplication where a part of the nucleotide sequence of a gene is repeated one or several times. This is a type of mutation that increases the rate of error in DNA.

Similarities Between Replication and Duplication of DNA

• Replication and duplication are two types of mechanisms that increase the amount of DNA inside the cell.
• Both have a role in the synthesis of an exact replica of the template strand in the form of complementary DNA.
• Moreover, the amount of chromatin inside the cell gets doubled in both processes.
• However, both processes do not increase the number of chromosomes or the ploidy of the cell.

Difference Between Replication and Duplication of DNA

Definition

Replication refers to the process by which a double-stranded DNA molecule is copied to produce two identical DNA molecules while duplication refers to the process by which the amount of DNA inside the nucleus gets doubled. Hence, this is the main difference between replication and duplication of DNA.

Significance

Furthermore, replication occurs prior to nuclear division while duplication is the doubling of the amount DNA inside the nucleus as a result of replication.

Importance

Another difference between replication and duplication of DNA is that replication doubles the cell’s genetic content, preparing the cell for the division while duplication does not increase the ploidy of the cell although the amount of DNA doubles.

Conclusion

In brief, replication is the process of synthesizing an exact replica of a DNA molecule, increasing the amount of DNA in the cell by twice. This prepares the cell for division. On the other hand, duplication refers to the increase in the amount of DNA by twice as a result of DNA replication. Therefore, the main difference between replication and duplication of DNA is their process. 

Reference:

1. “Replication.” Nature News, Nature Publishing Group, Available Here

Image Courtesy:

1. “0323 DNA Replication” By OpenStax – (CC BY 4.0) via Commons Wikimedia 
2. ‘Chromosomes during mitosis” By SyntaxError55 at the English language Wikipedia (CC BY-SA 3.0) via Commons Wikimedia

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