Difference Between Vertical and Horizontal Gene Transfer

Key Difference – Vertical vs Horizontal Gene Transfer
 

Gene transfer refers to the process that transfer or exchange genetic material between organisms. DNA which bears functional genes are exchanged among organisms causing the change in their genomic composition. It can occur in two types named vertical gene transfer and horizontal gene transfer. Horizontal gene transfer refers to the process in which genetic material is transferred between unrelated individuals. Vertical gene transfer refers to the process where genes are transferred from parent to their offspring. This is the key difference between vertical and horizontal gene transfer. Vertical gene transfer is common among organisms while horizontal gene transfer is less common.

CONTENTS
1. Overview and Key Difference
2. What is Vertical Gene Transfer
3. What is Horizontal Gene Transfer
4. Side by Side Comparison – Vertical vs Horizontal Gene Transfer
5. Summary

What is Vertical Gene Transfer?

Vertical gene transfer is a method of gene transferring from parent to their offspring. It can occur either through sexual reproduction or asexual reproduction or artificial mechanisms. This process is a common mechanism that happens between related organisms. Genomes are passed from one generation to the next generation occurs via vertical gene transferring in living organisms naturally. In plant breeding programs, vertical gene transferring is purposely done to transfer important genes to F1 generation. Two plants are crossed sexually to mix their genes and pass to the next generation. By doing this, valuable characteristics can be stored in the offspring allowing circulation in future generations.

In bacteria, the most common asexual reproduction method is binary fission. Binary fission results in two identical bacterial cells. It is an example of vertical gene transfer method of bacteria. In humans, the disease called AIDS is transmitting from parent mother to baby due to vertical gene transfer.

What is Horizontal Gene Transfer?

Horizontal gene transfer is a mechanism in which genetic material is transferred between nonrelated organisms. It is also known as lateral gene transfer. It occurs between different genomes such as between different species. Organisms acquire different characteristics through gene transferring. Horizontal gene transfer is different from the gene transferring from parent to offspring.

Horizontal gene transferring is made easy due to several types of DNA possessed by organisms. They are mainly mobile genetic elements such as transposons (jumping genes), plasmids (non-chromosomal circular DNA), and bacteriophages (bacteria infecting viruses). It occurs via several mechanisms as follows.

Horizontal Gene Transfer Mechanisms

Transformation

Prokaryotes are able to take up free DNA in the form of plasmids specially.

Bacterial Conjugation

 A mode of sexual reproduction that occurs between temporary connected two cells. During conjugation, F plasmids are transferred from donor to recipient resulting in genetic material transfer between two organisms as shown in figure 02. This is the main mechanism involves in horizontal gene transfer.

Transduction

Bacteriophage is able to inject its DNA into a bacterium when infected, which results in gene transferring between two bacteria during the second infection. This occurs via two processes named generalized and specialized transduction.

Uses of Horizontal Gene Transfer

Horizontal gene transfer is used in genetic engineering. Foreign DNA can be recombined or inserted into the genome of recipient organism in horizontal gene transferring. It allows recipients to acquire novel traits important for growth and survival. Horizontal gene transfer is extremely important in adaptation and evolution of both prokaryotes and eukaryotes. Favorable traits are filtered through natural selection and contributed to the evolution. Some organisms acquire genes that are valuable for adaptation and evolution through horizontal gene transfer. For example, acquisition of antibiotic resistivity by bacteria is a result of horizontal gene transfer.

Horizontal gene transfer is most favored among closely related taxa than highly different species. It can also occur between bacteria inhabiting in the same microenvironment.

What is the difference between Vertical and Horizontal Gene Transfer?

Summary – Vertical vs Horizontal Gene Transfer

Gene transfer can occur between related and non-related individuals. There are two main types of gene transferring named vertical and horizontal. Vertical gene transmission happens from parent to offspring. During reproduction or plant crossing, genes are transferred from parents to progeny. Horizontal gene transfer happens between different species which are not related. It is not feasible as vertical gene transferring. However due to mobile DNA elements such as plasmids, jumping genes and bacteriophages, genes exchange among organisms horizontally via conjugation, transduction and transformation. Horizontal gene transfer is common in bacteria and archaea than eukaryotes. This is the difference between vertical and horizontal gene transfer.

Reference:
1. Hotopp, Julie C. Dunning. “Horizontal gene transfer between bacteria and animals.” Trends in genetics : TIG. U.S. National Library of Medicine, Apr. 2011. Web. 09 May 2017
2. Rogers, Kara. “Horizontal gene transfer.” Encyclopædia Britannica. Encyclopædia Britannica, inc., 22 Nov. 2016. Web. 09 May 2017. https://www.britannica.com/science/horizontal-gene-transfer
3. Lacroix, Benoît. “Transfer of DNA from Bacteria to Eukaryotes.” MBio. N.p., 12 July 2016. Web. 09 May 2017

Image Courtesy:
1. “Binary Fission 2” By Ecoddington14 – https://commons.wikimedia.org/wiki/File:Binary_Fission.png (CC BY-SA 3.0) via Commons Wikimedia
2. “Conjugation” By Adenosine – Own work (CC BY-SA 3.0) via Commons Wikimedia