What is the Difference Between Vertical and Horizontal Gene Transfer

The main difference between vertical and horizontal gene transfer is that vertical gene transfer is the inheritance of DNA from the parent organisms whereas horizontal gene transfer is the acquisition of DNA from unrelated organisms. Furthermore, vertical gene transfer occurs via reproduction while horizontal gene transfer occurs either via transformation, transduction, or bacterial conjugation.

Vertical and horizontal gene transfer are two mechanisms of gene transfer which exchange functional genes between organisms. It is the basis for the development of gene therapy.

Key Areas Covered

1. What is Vertical Gene Transfer
     – Definition, Mechanisms, Importance
2. What is Horizontal Gene Transfer
     – Definition, Mechanisms, Importance
3. What are the Similarities Between Vertical and Horizontal Gene Transfer
     – Outline of Common Features
4. What is the Difference Between Vertical and Horizontal Gene Transfer
     – Comparison of Key Differences

Key Terms

Bacterial Conjugation, Horizontal Gene Transfer, Reproduction, Transduction, Transformation, Vertical Gene Transfer

Difference Between Vertical and Horizontal Gene Transfer - Comparison Summary

What is Vertical Gene Transfer

Vertical gene transfer is the transfer of genetic material from parent organisms to the offspring via reproduction. It involves both types of reproduction methods, i.e., sexual and asexual reproduction. During sexual reproduction, meiosis is responsible for the production of gametes with a half number of chromosomes in the parent cells. Subsequently, the fusion of gametes via fertilization restore the exact number of chromosomes in the parent cell.

For instance, there are two types of gametes as male gametes and female gametes. Male gametes have a paternal origin while female gametes have a maternal origin. Therefore, sexual reproduction involves combining genetic material which belongs to two different parent organisms. Hence, it increases genetic variation.

Difference Between Vertical and Horizontal Gene Transfer_Fig 01

Figure 1: Vertical and Horizontal Gene Transfer

However, in the case of asexual reproduction, mitosis is responsible for the production of new cells from the parent cells. Here, the daughter cells have the exact number of chromosomes as the parent cells. On the contrary to sexual reproduction, asexual reproduction does not increase the genetic diversity as the offsprings exhibit the same traits as their parents.

What is Horizontal Gene Transfer

Horizontal gene transfer is the movement of genetic information. It is the primary mechanism responsible for spreading of antibiotic resistance among bacteria. The three mechanisms involved in horizontal gene transfer are transformation, transduction, and bacterial conjugation. In transformation, bacteria are capable of uptaking foreign DNA from the surrounding environment.

Difference Between Vertical and Horizontal Gene Transfer_Fig 02

Figure 2: Horizontal Gene Transfer Mechanisms

In transduction, the transfer of genetic information occurs employing bacteriophages or bacterial viruses. On the other hand, in bacterial conjugation, bacteria transfer genes directly to another bacteria through pili. Besides, mobile DNA elements including transposable elements can pick up genes and insert into chromosomes or plasmids.

Similarities Between Vertical and Horizontal Gene Transfer

  • Vertical and horizontal gene transfer are two types of gene transfer mechanisms among organisms.
  • They are involved in the transfer of functional genes, which exert defined characters in the recipient.
  • Also, both mechanisms can increase genetic variation.

Difference Between Vertical and Horizontal Gene Transfer

Definition

Vertical gene transfer refers to the transmission of genetic material from a parent organism or organisms to the offsprings. Horizontal gene transfer refers to the acquisition of genetic information by an organism through transformation, transduction, or bacterial conjugation; for example, acquiring genetic information via the agency of a virus from an organism that is not its parent and is typically a member of a different species. Therefore, this is the main difference between vertical and horizontal gene transfer.

Relatedness

An important difference between vertical and horizontal gene transfer is that while vertical gene transfer occurs from parents to the offspring, horizontal gene transfer occurs between unrelated organisms.

Progeny

Moreover, vertical gene transfer produces a progeny while horizontal gene transfer does not produce a progeny and it occurs between two adult organisms. Thus, this is another difference between vertical and horizontal gene transfer.

Natural Mechanisms

One other difference between vertical and horizontal gene transfer is that the vertical gene transfer occurs either through asexual or sexual reproduction while horizontal gene transfer occurs either through transformation, transduction or bacterial conjugation.

Amount of Genetic Material Transferred

Furthermore, the vertical gene transfer transfers the whole genome but, the horizontal gene transfer transfers only fewer genes.

Importance

An additional difference between vertical and horizontal gene transfer is that the vertical gene transfer is responsible for the inheritance of parental traits to the offspring while the horizontal gene transfer introduces new traits to adult organisms.

Conclusion

Vertical gene transfer is the inheritance of a parent’s genetic material to the offspring during reproduction. A large amount of DNA, which is the whole genome, is transferred to the daughter organism during vertical gene transfer. On the other hand, horizontal gene transfer is the transfer of several genes from an adult organism to another adult organism. Here, these adult organisms are not related. This introduces new traits to the recipient. Therefore, the main difference between vertical and horizontal gene transfer is the type of organisms involved in, process, and the amount of DNA transferred.

Reference:

1. Burmeister, A. R., “Horizontal Gene Transfer” Evolution, medicine, and public health vol. 2015,1 193-4. 29 Jul. 2015, doi:10.1093/emph/eov018. Available Here

Image Courtesy:

1. “Horizontal and vertical gene transfer” By Gregorius Pilosus – Own work (CC BY-SA 3.0) via Commons Wikimedia 
2. “Bacterial horizontal gene transfer” By 2013MMG320B – Own work (CC BY-SA 3.0) via Commons Wikimedia  

About the Author: Lakna

Lakna, a graduate in Molecular Biology and Biochemistry, is a Molecular Biologist and has a broad and keen interest in the discovery of nature related things. She has a keen interest in writing articles regarding science.

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