What is the difference between strain and species?

The main difference between strain and species is that strain is a genetic variant; it is a subtype or culture of a biological species. However, species are the largest group of organisms in which any two individuals of the appropriate sex or mating type can produce   fruitful   Offspring , typically through sexual reproduction . In addition, several phyla can occur per species, whereby the species is the basic unit of classification or organisms and a unit of biodiversity .  

In short, strain and species are two units of classification of a living organism. However, their use may vary depending on the situation.  

Key areas covered  

1. What is a strain - definition, properties, use 2. What is a species - definition, properties, use 3. What are the similarities between strain and species - Overview of the similarities 4. What is the difference between strain and species - Comparison of the main differences

key terms  

Fertile offspring, genetic traits, species, strain, taxonomic group Difference Between Strain and Species - Summary of Comparison

What is a variety?  

A strain is a genetic variant, subtype, or culture of a biological species. They are more commonly used in microbiology. In addition, a strain comes from a single colony of cells, and microorganisms such as viruses, bacteria, and fungi have multiple strains within a species. As an example , a "flu strain" is a specific biological form of influenza   or "flu" virus, which is characterized by its different isoforms of surface proteins. One strain significantly carries a certain genetic trait that is not found in the other conspecifics.

Difference Between Tribe and Species

Figure 1: H1N1 virus strain

In addition, genetic variation is the variation of genomes between individuals of the same species due to the genetic mutations that occur during sexual reproduction. Usually, genetic variation can be caused by mutations of genes, gene flow, accidental mating, accidental fertilization, and cross between homologous chromosomes. In addition, genetic variation is an important mechanism that forces evolution through natural selection. It is also important to preserve biodiversity.

What is a species  

One species is a closely related group of organisms with similar characteristics that crossbreed to produce fertile offspring. It is also the basic unit of classification of organisms. To define a particular species, the similarities in the DNA sequences, morphological and ecological features can be taken into account. In historical terms, the emergence of species through natural selection is described by Charles Darwin in 1859. Sometimes a particular species can consist of different breeds with great variations. More often, similar species live in similar habitats because they come from a common ancestor. However, defining a species can become difficult due to variations within the species.

Key difference - strain vs. species

Figure 2: The Heliconius butterfly genus contains many similar species.

In addition, the species is a taxonomic level of organisms that ranks below a genus. Although made up of similar individuals who can crossbreed with one another, one species encompasses the largest possible gene pool. In addition, genes can be transferred between species through horizontal gene transfer. In addition, a certain species is scientifically named with a binomial name; the first part of it is the genus to which the organism belongs and the second part is the specific name. For example, humans have been scientifically considered homosexual. designated   Sapiens ; "Homo" is the genus to which humans belong and "Sapiens" is the specific name of humans.  

Similarities Between Tribe and Species  

  • In general, strain and species are two groups of living organisms classified according to different uses.  
  • In addition, the organisms within each group show similar genetic, morphological, and behavioral characteristics.  
  • In addition, the organisms within each group can successfully reproduce to produce fertile offspring.  

Difference Between Tribe and Species  


A strain refers to a genetic variant or subtype of a biological species, while species refers to a group of organisms that can reproduce with one another in nature and produce fertile offspring.  


A tribe is a subtype of species, while a species is the basic taxonomic group that classifies organisms.  


A strain is an isolate of a particular species with a particular genetic trait, while organisms of a species have a genetic similarity that is sufficient to mate and produce fertile offspring.  


A strain can be characterized by serotyping, enzyme type, functional traits and plasmid protein characterization , etc., while species can be characterized by genetic, biochemical and phenotypic criteria.  


In short, a strain is an isolate of a particular species that has a specific genetic trait compared to the other organisms of the same species. In general, a species refers to a group of organisms with some genetic similarity sufficient to produce fertile offspring by mating. Hence, a strain is a subtype or a genetic variant of a particular species, which species can have multiple strains. Hence, the main difference between strain and species lies in their genetics.   


1. Dijkshoorn, L. “Strain, Clone, and Species: Commentaries on Three Basic Concepts in Bacteriology.” J. Med. Mikrobiol. , Vol. 49, 2000, pp. 397-401. Available here .

Image courtesy:

1. "H1N1 navbox" From Cybercobra in the English Wikipedia ( CC BY-SA 3.0 ) via Commons Wikimedia 2. "Heliconius Mimicry" From see source - Repeating patterns of mimicry. Meyer A, PLoS Biology, Vol. 2, No. 04/10/2006, e341 doi: 10.1371 / journal.pbio.0040341 ( CC BY 2.5 ) via Commons Wikimedia

About the author: Lakna

Lakna, a graduate in molecular biology and biochemistry, is a molecular biologist and has a broad and strong interest in discovering things related to nature