Difference Between Somatic Variation and Germinal Variation

The key difference between somatic variation and germinal variation is that somatic variation is the genetic variation occurring in somatic cells while germinal variation is the genetic variation occurring in germ cells such as eggs or sperms.

Genetic variation refers to the process of changing the genetic material of an organism or the difference in DNA sequences between individuals within a population. DNA sequences subject to changes with time in a generation to generation. Genetic recombination is one of the main mechanisms that cause genetic variation. Furthermore, mutation also can cause genetic variation. Genetically, multicellular organisms possess two main types of cells; somatic cells and germ cells. Hence, genetic variation is of two types; they are the somatic variation and germinal variation. If the genetic variation occurs in somatic cells, we call it a somatic variation, and if the genetic variation occurs in the germ cells, we call it germinal variation. Somatic variations are mostly non-inheritable while germinal variations are mostly heritable.

CONTENTS

1. Overview and Key Difference
2. What is Somatic Variation
3. What is Germinal Variation
4. Similarities Between Somatic Variation and Germinal Variation
5. Side by Side Comparison – Somatic Variation vs Germinal Variation in Tabular Form
6. Summary

What is Somatic Variation?

When the genetic variation occurs in the somatic cells (all the other cells except germ cells), we call it as a somatic variation or acquired variation. Generally, somatic variations are harmless.

Furthermore, they don’t inherit into the next generation unlike germinal variation and are not significant as well. Also, somatic variations do not cause serious effects. Major causes for the somatic variation are the environmental factors such as exposure to ultraviolet radiation or certain chemicals.

What is Germinal Variation?

Germinal variation is the genetic variation that occurs in germ cells. It is also known as blastogenic variation. The genetic material of the gametes or the germ cells becomes mutated due to several reasons. These genetic variations can present in ancestors and transmit to offspring. Furthermore, they can arise suddenly due to the errors in the cell division. One of the major reasons for germinal variation is the recombination. During the sex cell formation by meiosis, chromosomal abnormalities can occur due to nondisjunction mutation, etc. Furthermore, radiation also can cause for germinal variation.

Unlike somatic variation that dies with the death of the individual, germinal variation is not dying. It is heritable since it occurs in germ cells. Furthermore, germinal variation causes fatal effects such as various syndromes and genetic disorders. In addition, germinal variations are evolutionary important and significant since they are inheriting from parent to offspring.

What are the Similarities Between Somatic Variation and Germinal Variation?

• Somatic variation and germinal variation are two types of genetic variation that are categorized based on the cell types.
• Both types arise due to the changes in the genetic material.
• They cause various diseases.

What is the Difference Between Somatic Variation and Germinal Variation?

Based on the cell type, there are two types of genetic variation namely somatic variation and germinal variation. The somatic variation occurs in somatic cells while the germinal variation occurs in germ cells. Therefore, this is the key difference between somatic variation and germinal variation. Furthermore, somatic variation is not heritable while the germinal variation is heritable. Hence, it is another difference between somatic variation and germinal variation. In addition, somatic variations are not significant, and they do not involve with the evolution of the species. On the other hand, germinal variations are significant, and they provide the raw material for evolution. Thus, this is another difference between somatic variation and germinal variation.

The below infographic on the difference between somatic variation and germinal variation provides more differences between both.

Summary – Somatic Variation vs Germinal Variation

When the genetic variation takes place in somatic cells, we call it somatic variation. On the other hand, when the genetic variation takes place in sex cells, we call it germinal variation. Hence, the key difference between somatic variation and germinal variation depends on the cell type. Furthermore, somatic variations are not inheriting from parents and also not transmitted to the next generation. However, germinal variations are inheriting from ancestors and also transmitting to next generations. Thus, this is the difference between somatic variation and germinal variation.

Reference:

1. “What Is Genetic Variation?” The European Bioinformatics Institute < EMBL-EBI, 26 Sept. 2017. Available here  

Image Courtesy:

1.”DNA UV mutation”By NASA/David Herring – NASA, [1], (Public Domain) via Commons Wikimedia  
2.”Figure 12 03 04″By CNX OpenStax (CC BY 4.0) via Commons Wikimedia